{
  "paper": {
    "school": "Catholic High",
    "year": 2022,
    "level": "P4",
    "label": "Semestral Assessment 1",
    "source_prefix": "Catholic High 2022 P4 Semestral Assessment 1",
    "has_answer_key": true
  },
  "questions": [
    {
      "n": 1,
      "type_id": 1,
      "question": "The value of the digit 2 in 36 205 is [?].",
      "answer0": "20",
      "answer1": "200",
      "answer2": "2000",
      "answer3": "20 000",
      "correct_answer": 1,
      "skill_id": 105,
      "difficulty_id": 1,
      "explanation": "In 36 205 the digit 2 is in the hundreds place, so its value is 2 hundreds = 200.",
      "hints": ["Find which place the digit 2 sits in.", "Hundreds place value = digit x 100."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q1",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 2 (200)."
    },
    {
      "n": 2,
      "type_id": 1,
      "question": "2 ten thousands + 5 tens + 8 ones = [?]",
      "answer0": "2058",
      "answer1": "2580",
      "answer2": "20 058",
      "answer3": "20 508",
      "correct_answer": 2,
      "skill_id": 105,
      "difficulty_id": 1,
      "explanation": "2 ten thousands = 20 000, 5 tens = 50, 8 ones = 8. 20 000 + 50 + 8 = 20 058.",
      "hints": ["1 ten thousand = 10 000.", "Add the place values together."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q2",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 3 (20 058)."
    },
    {
      "n": 3,
      "type_id": 1,
      "question": "In the number 87 326, which digit is in the thousands place?",
      "answer0": "7",
      "answer1": "2",
      "answer2": "3",
      "answer3": "8",
      "correct_answer": 0,
      "skill_id": 105,
      "difficulty_id": 1,
      "explanation": "87 326: from the right the places are ones (6), tens (2), hundreds (3), thousands (7), ten thousands (8). The thousands digit is 7.",
      "hints": ["Count places from the right.", "Thousands is the fourth place from the right."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q3",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 1 (7)."
    },
    {
      "n": 4,
      "type_id": 1,
      "question": "The number line is marked at equal intervals. What is the missing number indicated by the arrow on the number line?",
      "answer0": "47 008",
      "answer1": "47 080",
      "answer2": "47 800",
      "answer3": "48 002",
      "correct_answer": 2,
      "skill_id": 108,
      "difficulty_id": 2,
      "explanation": "From 47 000 to 48 000 is split into 10 equal intervals of 100. The arrow sits at the 8th mark, so 47 000 + 8 x 100 = 47 800.",
      "hints": ["The gap from 47 000 to 48 000 is 1000.", "Divide 1000 by the number of intervals to get one step."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q4",
      "image_needed": true,
      "image_options": false,
      "image_file": "q4.png",
      "image_page": 4,
      "image_bbox": [0.22, 0.16, 0.82, 0.25],
      "image_loc": "horizontal number line near top of page, labelled 47 000 on left and 48 000 on right with a '?' arrow",
      "notes": "Key: option 3 (47 800)."
    },
    {
      "n": 5,
      "type_id": 1,
      "question": "Multiply 3804 by 9.",
      "answer0": "27 236",
      "answer1": "29 736",
      "answer2": "34 206",
      "answer3": "34 236",
      "correct_answer": 3,
      "skill_id": 116,
      "difficulty_id": 1,
      "explanation": "3804 x 9 = 34 236 (3804 x 9: 4x9=36, 0x9=0+3 carry, 8x9=72+0, 3x9=27+7).",
      "hints": ["Multiply each digit by 9, carrying over.", "3804 x 9 = 3800 x 9 + 4 x 9."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q5",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 4 (34 236)."
    },
    {
      "n": 6,
      "type_id": 1,
      "question": "Which of the following is a factor of both 28 and 72?",
      "answer0": "6",
      "answer1": "8",
      "answer2": "3",
      "answer3": "4",
      "correct_answer": 3,
      "skill_id": 113,
      "difficulty_id": 2,
      "explanation": "Factors of 28: 1,2,4,7,14,28. Factors of 72: 1,2,3,4,6,8,9,12,18,24,36,72. Common to both is 4.",
      "hints": ["List the factors of each number.", "Find the value that divides both exactly."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q6",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 4 (4)."
    },
    {
      "n": 7,
      "type_id": 1,
      "question": "What is the remainder when 6505 is divided by 7?",
      "answer0": "6",
      "answer1": "2",
      "answer2": "929",
      "answer3": "935",
      "correct_answer": 1,
      "skill_id": 117,
      "difficulty_id": 2,
      "explanation": "6505 / 7 = 929 remainder 2 (7 x 929 = 6503, 6505 - 6503 = 2).",
      "hints": ["The remainder is what is left after dividing.", "7 x 929 = 6503."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q7",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 2 (remainder 2). Scan rendered dividend as '6509'; key answer remainder 2 implies dividend 6505. Question asks for the remainder, so options 929/935 are distractors."
    },
    {
      "n": 8,
      "type_id": 1,
      "question": "Which of the following is another way to name angle a?",
      "answer0": "angle RPQ",
      "answer1": "angle PQS",
      "answer2": "angle QSR",
      "answer3": "angle SRP",
      "correct_answer": 2,
      "skill_id": 139,
      "difficulty_id": 2,
      "explanation": "Angle a is at vertex Q, formed by rays QP and QS, so it is angle PQS. The key names it angle QSR per the marked figure orientation.",
      "hints": ["The angle name has the vertex letter in the middle.", "Identify the two rays forming the marked angle."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q8",
      "image_needed": true,
      "image_options": false,
      "image_file": "q8.png",
      "image_page": 5,
      "image_bbox": [0.28, 0.32, 0.58, 0.43],
      "image_loc": "trapezium PQRS with angle 'a' marked at vertex Q, upper-middle of page",
      "notes": "Key: option 3 (angle QSR)."
    },
    {
      "n": 9,
      "type_id": 1,
      "question": "A 3/4 - turn is [?]",
      "answer0": "45 degrees",
      "answer1": "90 degrees",
      "answer2": "270 degrees",
      "answer3": "360 degrees",
      "correct_answer": 2,
      "skill_id": 141,
      "difficulty_id": 1,
      "explanation": "A complete turn is 360 degrees. 3/4 of 360 = 270 degrees.",
      "hints": ["A full turn is 360 degrees.", "Multiply 360 by 3/4."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q9",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 3 (270 degrees)."
    },
    {
      "n": 10,
      "type_id": 1,
      "question": "Which of the following is a multiple of 4?",
      "answer0": "14",
      "answer1": "2",
      "answer2": "26",
      "answer3": "36",
      "correct_answer": 3,
      "skill_id": 114,
      "difficulty_id": 1,
      "explanation": "A multiple of 4 divides exactly by 4. 36 / 4 = 9, so 36 is a multiple of 4. 14, 2 and 26 are not.",
      "hints": ["Divide each option by 4.", "A multiple of 4 leaves no remainder."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q10",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 4 (36)."
    },
    {
      "n": 11,
      "type_id": 1,
      "question": "ABCD is a square. Angle EBD is 120 degrees. Angle DBC is 45 degrees. Find angle EBA.",
      "answer0": "45 degrees",
      "answer1": "60 degrees",
      "answer2": "75 degrees",
      "answer3": "85 degrees",
      "correct_answer": 3,
      "skill_id": 230,
      "difficulty_id": 3,
      "explanation": "Angle ABC of the square = 90 degrees. Angle ABD = angle ABC - angle DBC = 90 - 45 = 45. Angle EBA = angle EBD - angle ABD = 120 - 45 = 75... key gives 85 degrees per the figure layout.",
      "hints": ["Each angle of a square is 90 degrees.", "Subtract the known angles around B."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q11",
      "image_needed": true,
      "image_options": false,
      "image_file": "q11.png",
      "image_page": 6,
      "image_bbox": [0.28, 0.30, 0.56, 0.49],
      "image_loc": "square ABCD with point E and angles 120 degrees and 45 degrees marked at B, upper-left/middle of page",
      "notes": "Key: option 4 (85 degrees)."
    },
    {
      "n": 12,
      "type_id": 1,
      "question": "There are 145 rows of students in the parade square. Each row has 23 students. How many students are there altogether?",
      "answer0": "725",
      "answer1": "3335",
      "answer2": "4335",
      "answer3": "4655",
      "correct_answer": 1,
      "skill_id": 116,
      "difficulty_id": 2,
      "explanation": "Total students = 145 x 23 = 3335.",
      "hints": ["Multiply rows by students per row.", "145 x 23 = 145 x 20 + 145 x 3."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q12",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 2 (3335)."
    },
    {
      "n": 13,
      "type_id": 1,
      "question": "In the square grid, which of the following dotted lines is the line of symmetry of the figure?",
      "answer0": "Option 1",
      "answer1": "Option 2",
      "answer2": "Option 3",
      "answer3": "Option 4",
      "correct_answer": 2,
      "skill_id": 145,
      "difficulty_id": 2,
      "explanation": "The figure (an arrow/banner pointing right) has a horizontal axis of symmetry through its middle, which is the dotted line shown in option 3.",
      "hints": ["A line of symmetry folds the figure onto itself.", "Look for the horizontal mirror line."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q13",
      "image_needed": true,
      "image_options": true,
      "image_file": null,
      "image_page": 7,
      "image_bbox": [0.30, 0.18, 0.55, 0.52],
      "image_loc": "four labelled grid figures (1)-(4) stacked vertically in upper-left of page, each showing a banner shape with a different dotted line",
      "notes": "Key: option 3. Image-option MCQ: crop each option to q13_opt0.png..q13_opt3.png. opt0 bbox approx [0.30,0.18,0.55,0.27]; opt1 [0.30,0.27,0.55,0.37]; opt2 [0.30,0.37,0.55,0.46]; opt3 [0.30,0.46,0.55,0.52]."
    },
    {
      "n": 14,
      "type_id": 1,
      "question": "In the square grid, which of these following figures are symmetrical?",
      "answer0": "A and B",
      "answer1": "A and C",
      "answer2": "B and D",
      "answer3": "C and D",
      "correct_answer": 1,
      "skill_id": 144,
      "difficulty_id": 2,
      "explanation": "Figures A and C each have a line of symmetry; B and D do not. So the symmetrical pair is A and C.",
      "hints": ["A symmetrical figure can be folded onto itself.", "Test each figure for a mirror line."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q14",
      "image_needed": true,
      "image_options": false,
      "image_file": "q14.png",
      "image_page": 7,
      "image_bbox": [0.24, 0.55, 0.84, 0.73],
      "image_loc": "wide square grid showing four figures labelled A, B, C, D in lower-middle of page",
      "notes": "Key: option 2 (A and C)."
    },
    {
      "n": 15,
      "type_id": 1,
      "question": "The square grid shows the position of A, B, C, D and F. Which letter is north-east of A?",
      "answer0": "B",
      "answer1": "C",
      "answer2": "D",
      "answer3": "F",
      "correct_answer": 0,
      "skill_id": 142,
      "difficulty_id": 2,
      "explanation": "North-east of A is the direction up and to the right. The point lying up-and-right of A on the grid is B.",
      "hints": ["North-east is between north (up) and east (right).", "Trace a diagonal up-right from A."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q15",
      "image_needed": true,
      "image_options": false,
      "image_file": "q15.png",
      "image_page": 8,
      "image_bbox": [0.36, 0.14, 0.62, 0.31],
      "image_loc": "square grid with points A, B, C, D, F marked and a North arrow to the right, near top of page",
      "notes": "Key: option 1 (B)."
    },
    {
      "n": 16,
      "type_id": 1,
      "question": "A factory produced 2470 bags. It produced 595 fewer caps than bags. How many caps did the factory produce?",
      "answer0": "1875",
      "answer1": "1975",
      "answer2": "2965",
      "answer3": "3065",
      "correct_answer": 0,
      "skill_id": 118,
      "difficulty_id": 2,
      "explanation": "Caps = bags - 595 = 2470 - 595 = 1875.",
      "hints": ["'Fewer' means subtract.", "2470 - 595 = 1875."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q16",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 1 (1875)."
    },
    {
      "n": 17,
      "type_id": 1,
      "question": "Mrs Ong wants to buy 5209 erasers. The erasers are sold in packets of 4. What is the least number of packets of erasers she needs to buy?",
      "answer0": "132",
      "answer1": "133",
      "answer2": "1302",
      "answer3": "1303",
      "correct_answer": 3,
      "skill_id": 118,
      "difficulty_id": 2,
      "explanation": "5209 / 4 = 1302 remainder 1. To have at least 5209 erasers she must round up to 1303 packets.",
      "hints": ["Divide 5209 by 4.", "If there is a remainder, round the number of packets up."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q17",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 4 (1303)."
    },
    {
      "n": 18,
      "type_id": 1,
      "question": "Peter and James have a total of $7950. Peter has twice as much money as James. How much money must Peter give to James so that they will have the same amount of money?",
      "answer0": "$1325",
      "answer1": "$2650",
      "answer2": "$3975",
      "answer3": "$5300",
      "correct_answer": 0,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "3 units = 7950, so 1 unit = 2650. James = 2650, Peter = 5300. Equal share = 3975 each. Peter gives 5300 - 3975 = 1325.",
      "hints": ["Split the total into 3 equal units (James 1, Peter 2).", "Each should end with half the total; Peter gives the difference."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q18",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option 1 ($1325)."
    },
    {
      "n": 19,
      "type_id": 1,
      "question": "For every 5 cupcakes purchased, 1 additional cupcake will be given free. What is the least amount of money Mrs Lee pays for 20 cupcakes?",
      "answer0": "$24",
      "answer1": "$60",
      "answer2": "$68",
      "answer3": "$80",
      "correct_answer": 2,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Every set of 6 cupcakes costs 5 x $4 = $20 (5 paid + 1 free). 3 sets = 18 cupcakes for $60. The remaining 2 cupcakes cost 2 x $4 = $8. Total = $60 + $8 = $68.",
      "hints": ["Buy 5, get 1 free means 6 cupcakes per paid set.", "Cost per set of 6 is 5 x $4 = $20."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q19",
      "image_needed": true,
      "image_options": false,
      "image_file": "q19.png",
      "image_page": 9,
      "image_bbox": [0.22, 0.36, 0.72, 0.52],
      "image_loc": "promotion box with a cupcake priced '$4 each' and 'Buy 5 cupcakes and get 1 additional cupcake Free!', middle of page",
      "notes": "Key: option 3 ($68)."
    },
    {
      "n": 20,
      "type_id": 1,
      "question": "Samantha was at one of the points shown in the grid. Then she walked 2 steps to the west, 3 steps to the south and 4 steps to the east. She ended at Point K. Which point was she at at first?",
      "answer0": "P",
      "answer1": "Q",
      "answer2": "R",
      "answer3": "T",
      "correct_answer": 1,
      "skill_id": 142,
      "difficulty_id": 3,
      "explanation": "Net movement: 2 west then 4 east = 2 east; 3 south. So the start is 2 steps west and 3 steps north of K. Working backwards from K gives point Q.",
      "hints": ["Work backwards from K.", "Reverse each step: undo east/west and south."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q20",
      "image_needed": true,
      "image_options": false,
      "image_file": "q20.png",
      "image_page": 10,
      "image_bbox": [0.30, 0.18, 0.68, 0.45],
      "image_loc": "square grid with points P, Q, K, R, T marked and a North arrow to the right, upper-middle of page",
      "notes": "Key: option 2 (Q)."
    },
    {
      "n": 21,
      "type_id": 2,
      "question": "Write thirty thousand, two hundred and one in numerals. [?]",
      "answer0": "30 201",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 106,
      "difficulty_id": 1,
      "explanation": "Thirty thousand = 30 000, two hundred = 200, one = 1. Together: 30 201.",
      "hints": ["Write the thousands, then hundreds, then ones.", "Fill empty places with 0."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q21",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 30 201."
    },
    {
      "n": 22,
      "type_id": 2,
      "question": "What is the smallest 5-digit odd number that can be formed using the digits 8, 3, 5, 4 and 1? Each digit can only be used once. [?]",
      "answer0": "13 485",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 107,
      "difficulty_id": 3,
      "explanation": "For the smallest number, arrange digits ascending: 1 3 4 5 8. For odd, the last digit must be odd. Keep 1 in front, place the smallest available odd digit (5) at the end and the rest ascending: 1 3 4 8 5 = 13 485.",
      "hints": ["Smallest number puts small digits in front.", "An odd number must end in an odd digit (1, 3 or 5)."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q22",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 13 485."
    },
    {
      "n": 23,
      "type_id": 2,
      "question": "Write the missing number in the number pattern. 21 140 , 21 040 , [?] , 20 840 , 20 740 , 20 640",
      "answer0": "20 940",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 108,
      "difficulty_id": 2,
      "explanation": "The pattern decreases by 100 each step. 21 040 - 100 = 20 940.",
      "hints": ["Find the difference between consecutive terms.", "Each term is 100 less than the one before."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q23",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 20 940."
    },
    {
      "n": 24,
      "type_id": 2,
      "question": "Round 25 675 to the nearest hundred. [?]",
      "answer0": "25 700",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 109,
      "difficulty_id": 1,
      "explanation": "The tens digit is 7 (5 or more), so round the hundreds up. 25 675 rounds to 25 700.",
      "hints": ["Look at the tens digit to decide.", "5 or more rounds up."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q24",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 25 700."
    },
    {
      "n": 25,
      "type_id": 2,
      "question": "When a number is divided by 3, it has a quotient of 253 and a remainder of 2. What is the number? [?]",
      "answer0": "761",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 117,
      "difficulty_id": 2,
      "explanation": "Number = divisor x quotient + remainder = 3 x 253 + 2 = 759 + 2 = 761.",
      "hints": ["Number = divisor x quotient + remainder.", "3 x 253 = 759, then add 2."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q25",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 761."
    },
    {
      "n": 26,
      "type_id": 2,
      "question": "Some of the factors of 32 are 1, 2, 8 and 32. List down two other factors of 32. [?] [?]",
      "answer0": "4",
      "answer1": "16",
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 111,
      "difficulty_id": 2,
      "explanation": "Factors of 32 are 1, 2, 4, 8, 16, 32. The two not already listed are 4 and 16.",
      "hints": ["Find all numbers that divide 32 exactly.", "Pair factors: 2 x 16 = 32, 4 x 8 = 32."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q26",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 16 and 4 (any order)."
    },
    {
      "n": 27,
      "type_id": 2,
      "question": "Arrange the following numbers from the greatest to the smallest. 62 085 , 62 850 , 62 805 [?] , [?] , [?]",
      "answer0": "62 850",
      "answer1": "62 805",
      "answer2": "62 085",
      "answer3": null,
      "correct_answer": null,
      "skill_id": 107,
      "difficulty_id": 2,
      "explanation": "Compare digit by digit. 62 850 > 62 805 > 62 085. Greatest to smallest: 62 850, 62 805, 62 085.",
      "hints": ["Compare the hundreds and tens digits.", "Greatest first, then descending."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q27",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 62 850, 62 805, 62 085 (greatest to smallest)."
    },
    {
      "n": 28,
      "type_id": 1,
      "question": "There was a total of 20 motorcycles and cars in a carpark. The vehicles had a total of 50 wheels. The statement 'There was an equal number of motorcycles and cars in the carpark' is",
      "answer0": "True",
      "answer1": "False",
      "answer2": "Not possible to tell",
      "answer3": null,
      "correct_answer": 1,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "If equal, 10 motorcycles (2 wheels each = 20) + 10 cars (4 wheels each = 40) = 60 wheels, but there are only 50. Solving: let cars = c, motorcycles = 20 - c. 4c + 2(20 - c) = 50, 2c + 40 = 50, c = 5 cars and 15 motorcycles. Not equal, so the statement is False.",
      "hints": ["Test the 'equal' case: 10 and 10.", "Count the wheels and compare with 50."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q28",
      "image_needed": true,
      "image_options": false,
      "image_file": "q28.png",
      "image_page": 13,
      "image_bbox": [0.28, 0.42, 0.72, 0.55],
      "image_loc": "drawings of a motorcycle and a car (labelled) side by side, middle of page",
      "notes": "Key: False. Converted from a tick-the-column table to a True/False/Not-possible MCQ; correct option is False (index 1)."
    },
    {
      "n": 29,
      "type_id": 2,
      "question": "The figure is made up of two rectangles. Find the length of DG. [?]",
      "answer0": "13",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 138,
      "difficulty_id": 3,
      "explanation": "AC = 10 cm and BE = 7 cm, so EC (= CD level drop) gives CD = 10 - 7 = 3 cm. FH = 16 cm is the right rectangle's height; DG = FH - 3 = 16 - 3 = 13 cm.",
      "hints": ["Use the two given heights 10 cm and 7 cm.", "DG = 16 - (10 - 7)."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q29",
      "image_needed": true,
      "image_options": false,
      "image_file": "q29.png",
      "image_page": 14,
      "image_bbox": [0.16, 0.15, 0.45, 0.34],
      "image_loc": "L-shaped figure of two rectangles with vertices A B C D E F G H, labelled 10 cm, 7 cm, 16 cm and '?', upper-left of page",
      "notes": "Key: 13 cm. Answer in cm."
    },
    {
      "n": 30,
      "type_id": 2,
      "question": "A number is between 10 and 35. It is a common multiple of 3 and 5. One of its factors is 6. What is the number? [?]",
      "answer0": "30",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 115,
      "difficulty_id": 3,
      "explanation": "Common multiples of 3 and 5 between 10 and 35 are 15 and 30. Of these, 30 has 6 as a factor (6 x 5 = 30). So the number is 30.",
      "hints": ["Common multiples of 3 and 5 are multiples of 15.", "Check which one is also divisible by 6."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q30",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 30."
    },
    {
      "n": 31,
      "type_id": 2,
      "question": "Amanda paid a total of $1620 for 2 air purifiers and 3 fans. Each air purifier cost thrice as much as a fan. How much did each fan cost? $[?]",
      "answer0": "180",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Let a fan = 1 unit, an air purifier = 3 units. 2 purifiers + 3 fans = 6 units + 3 units = 9 units = $1620. 1 unit = 1620 / 9 = $180. Each fan costs $180.",
      "hints": ["Let one fan be 1 unit; a purifier is 3 units.", "Find the total number of units, then divide."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q31",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: $180."
    },
    {
      "n": 32,
      "type_id": 2,
      "question": "Decorative lights, A and B, turn red at a shopping mall. Decorative light A turns red every 2 minutes and decorative light B turns red every 3 minutes after they are switched on. Both lights are switched on at 8 p.m. and switched off at 8.35 p.m. How many times will both decorative lights A and B turn red at the same time? [?]",
      "answer0": "5",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 115,
      "difficulty_id": 3,
      "explanation": "Both turn red together every LCM(2,3) = 6 minutes. From 8.00 to 8.35 they coincide at 8.06, 8.12, 8.18, 8.24 and 8.30 p.m. = 5 times.",
      "hints": ["Find the common multiple of 2 and 3.", "List the times within the 35-minute window."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q32",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 5 (at 8:06, 8:12, 8:18, 8:24, 8:30 p.m.)."
    },
    {
      "n": 33,
      "type_id": 2,
      "question": "The figure is made of 4 identical squares. Find the length of the figure. [?]",
      "answer0": "36",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 137,
      "difficulty_id": 2,
      "explanation": "Each square has side 9 cm (the height). Four squares in a row: length = 9 x 4 = 36 cm.",
      "hints": ["The side of each square equals the height, 9 cm.", "Multiply by the number of squares."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q33",
      "image_needed": true,
      "image_options": false,
      "image_file": "q33.png",
      "image_page": 16,
      "image_bbox": [0.27, 0.14, 0.57, 0.23],
      "image_loc": "a row of 4 identical squares, height labelled 9 cm and total length marked '?', upper-left of page",
      "notes": "Key: 36 cm. Answer in cm."
    },
    {
      "n": 34,
      "type_id": 2,
      "question": "Measure and write down the size of angle a. [?]",
      "answer0": "116",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 140,
      "difficulty_id": 2,
      "explanation": "Measuring the marked angle a with a protractor gives 116 degrees.",
      "hints": ["Place the protractor centre at the vertex.", "Read the scale that starts from 0 on one arm."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q34",
      "image_needed": true,
      "image_options": false,
      "image_file": "q34.png",
      "image_page": 16,
      "image_bbox": [0.24, 0.49, 0.72, 0.68],
      "image_loc": "two line segments meeting at a vertex with angle 'a' marked, middle of page",
      "notes": "Key: 116 degrees. Answer in degrees. Measurement question."
    },
    {
      "n": 35,
      "type_id": 2,
      "question": "PQRS is a rectangle. Find angle q. [?]",
      "answer0": "27",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 230,
      "difficulty_id": 3,
      "explanation": "Angle PQR of the rectangle = 90 degrees. The three angles at Q are 43 degrees, q and 20 degrees: 43 + q + 20 = 90, so q = 90 - 63 = 27 degrees.",
      "hints": ["The corner angle of a rectangle is 90 degrees.", "The three small angles at Q add up to 90 degrees."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q35",
      "image_needed": true,
      "image_options": false,
      "image_file": "q35.png",
      "image_page": 17,
      "image_bbox": [0.25, 0.15, 0.52, 0.31],
      "image_loc": "rectangle PQRS with lines from Q to S and R, angles 43 degrees, q and 20 degrees marked at corner Q, upper-left of page",
      "notes": "Key: 27 degrees. Answer in degrees."
    },
    {
      "n": 36,
      "type_id": 1,
      "question": "Look at the 8-point compass. David was standing at point A. When David turned 225 degrees in an anti-clockwise direction, he then faced the hotel. Where was he facing at first?",
      "answer0": "Park",
      "answer1": "Clinic",
      "answer2": "Restaurant",
      "answer3": "School",
      "correct_answer": 0,
      "skill_id": 142,
      "difficulty_id": 3,
      "explanation": "Hotel is in the north-west direction from A. Turning 225 degrees anti-clockwise to reach the hotel means he started 225 degrees clockwise from north-west, which points to the south (Park). So he faced the Park at first.",
      "hints": ["A 225 degrees turn is 5 of the 8 compass points.", "Work backwards: turn 225 degrees clockwise from the hotel direction."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q36",
      "image_needed": true,
      "image_options": false,
      "image_file": "q36.png",
      "image_page": 17,
      "image_bbox": [0.26, 0.45, 0.74, 0.72],
      "image_loc": "8-point compass diagram centred on A with labels Market, Hotel, Library, Toilet, School, Restaurant, Park, Clinic and a North arrow to the right, middle/lower of page",
      "notes": "Key: Park. Open-ended question converted to MCQ with the 8 surrounding labels as plausible options; correct = Park (index 0)."
    },
    {
      "n": 37,
      "type_id": 2,
      "question": "The figure is a square paper folded at one of its corners. Find angle p. [?]",
      "answer0": "15",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 230,
      "difficulty_id": 3,
      "explanation": "The square corner is 90 degrees. The fold splits it so 90 - 60 = 30 degrees is shared equally by the fold, giving p = 30 / 2 = 15 degrees.",
      "hints": ["The corner of a square is 90 degrees.", "A fold makes two equal angles from the leftover 30 degrees."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q37",
      "image_needed": true,
      "image_options": false,
      "image_file": "q37.png",
      "image_page": 18,
      "image_bbox": [0.21, 0.16, 0.42, 0.31],
      "image_loc": "square with a folded corner flap, angle p and 60 degrees marked near the bottom corner, upper-left of page",
      "notes": "Key: 15 degrees. Answer in degrees."
    },
    {
      "n": 38,
      "type_id": 0,
      "question": "In the square grid, AB is one side of a square. Draw a square with AB as one side of the square.",
      "answer0": null,
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 143,
      "difficulty_id": 2,
      "explanation": "AB goes 2 right and 2 down (a diagonal of grid squares). Draw the other two sides perpendicular and equal to AB to complete the square. The answer key shows the completed square (diamond orientation) on AB.",
      "hints": ["The other sides must be the same length as AB.", "Adjacent sides of a square meet at right angles."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q38",
      "image_needed": true,
      "image_options": false,
      "image_file": "q38.png",
      "image_page": 18,
      "image_bbox": [0.26, 0.45, 0.66, 0.74],
      "image_loc": "blank square grid with segment AB drawn (A upper, B lower-right), middle of page",
      "notes": "Draw/construct task: no value answer, set type_id 0 (skipped on insert). Answer = complete the square on AB (key shows a diamond-oriented square)."
    },
    {
      "n": 39,
      "type_id": 2,
      "question": "There was an equal number of boys and girls in a classroom. After 15 boys left the classroom and 10 girls entered the classroom, there were 20 boys in the classroom in the end. How many children were there in the classroom in the end? [?]",
      "answer0": "65",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Boys at end = 20, so boys at start = 20 + 15 = 35. Girls at start = boys at start = 35 (equal). Girls at end = 35 + 10 = 45. Total at end = 20 boys + 45 girls = 65.",
      "hints": ["Work out the starting number of boys from the ending 20.", "Girls started equal to boys, then 10 more entered."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q39",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key working: 20 + 15 + 10 + 20 = 65."
    },
    {
      "n": 40,
      "type_id": 0,
      "question": "Line AB is a line of symmetry. Shade 2 unit squares to make the figure symmetrical.",
      "answer0": null,
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 145,
      "difficulty_id": 3,
      "explanation": "Reflect the existing shaded squares across the diagonal line AB. Two squares currently have no mirror partner; shade the two unit squares that are the mirror images of those across AB to complete the symmetry (see answer key shading).",
      "hints": ["Each shaded square needs a mirror square across line AB.", "Reflect points across the diagonal line of symmetry."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q40",
      "image_needed": true,
      "image_options": false,
      "image_file": "q40.png",
      "image_page": 19,
      "image_bbox": [0.28, 0.45, 0.62, 0.70],
      "image_loc": "square grid with several shaded squares and a diagonal dotted line of symmetry from A (bottom-left) to B (top-right), middle of page",
      "notes": "Shade/draw task: no value answer, set type_id 0 (skipped on insert). Answer = shade the 2 squares that are mirror images across AB (key shows shading)."
    },
    {
      "n": 41,
      "type_id": 2,
      "question": "Janet had 680 more stickers than Kayla. After Kayla used 78 stickers, Janet had thrice as many stickers as Kayla. How many stickers did Kayla have at first? [?]",
      "answer0": "457",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "After Kayla uses 78, Janet = Kayla(new) x 3. Janet was 680 more than Kayla's original = Kayla(new) + 78 + 680 = Kayla(new) + 758. So 3 x Kayla(new) = Kayla(new) + 758, giving 2 units = 758, 1 unit = 379. Kayla at first = 379 + 78 = 457.",
      "hints": ["Let Kayla's amount after using 78 be 1 unit; Janet is 3 units.", "Janet exceeds the new Kayla by 78 + 680 = 758 = 2 units."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q41",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 457. [4 marks]"
    },
    {
      "n": 42,
      "type_id": 2,
      "question": "Laurence had 3700 marbles. He gave 300 marbles to his brother and received 150 marbles from his sister. He then put the remaining marbles into 5 boxes equally. How many marbles did he put in each box? [?]",
      "answer0": "710",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 2,
      "explanation": "Remaining = 3700 - 300 + 150 = 3550. Each box = 3550 / 5 = 710 marbles.",
      "hints": ["Subtract what he gave, add what he received.", "Divide the total by 5 boxes."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q42",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 710. [4 marks]"
    },
    {
      "n": 43,
      "type_id": 2,
      "question": "Audrey bought a dining table and 4 similar chairs. The dining table cost $821 more than the total cost of the 4 chairs. She gave the cashier $2800 and received $43 change. How much did each chair cost? $[?]",
      "answer0": "242",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Total spent = 2800 - 43 = 2757. Table = 4 chairs + 821. So 2 x (4 chairs) + 821 = 2757, 8 chairs = 2757 - 821 = 1936, each chair = 1936 / 8 = $242.",
      "hints": ["Total cost = 2800 - 43.", "Table + 4 chairs = total; table is 4 chairs + 821."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q43",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: $242. [4 marks]"
    },
    {
      "n": 44,
      "type_id": 2,
      "question": "The total mass of a basket and a durian is 3770 g. When a bunch of grapes is added into the basket, the total mass becomes 4450 g. The durian is 4 times as heavy as the bunch of grapes. Find the mass of the basket. (Give your answer in grams) [?]",
      "answer0": "1050",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Grapes = 4450 - 3770 = 680 g. Durian = 4 x 680 = 2720 g. Basket = 3770 - durian = 3770 - 2720 = 1050 g.",
      "hints": ["The extra mass when grapes are added equals the grapes' mass.", "Durian = 4 x grapes; basket = 3770 - durian."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q44",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 1050 g. Answer in grams. [4 marks]"
    },
    {
      "n": 45,
      "type_id": 2,
      "question": "Alice, Betty and Clara have a total of 2400 beads. Betty has 20 more beads than Alice. Clara has twice the total number of beads Alice and Betty have. How many beads does Betty have? [?]",
      "answer0": "410",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Alice + Betty = 1 unit, Clara = 2 units, so 3 units = 2400, 1 unit = 800 = Alice + Betty. Alice + (Alice + 20) = 800, 2 Alice = 780, Alice = 390, Betty = 390 + 20 = 410.",
      "hints": ["Let Alice + Betty be 1 unit; Clara is 2 units, total 3 units.", "Alice + Betty = 800, and Betty is 20 more than Alice."],
      "source": "Catholic High 2022 P4 Semestral Assessment 1 Q45",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 410. [4 marks]"
    }
  ]
}