{
  "paper": {
    "school": "CHIJ St Nicholas Girls' School",
    "year": 2022,
    "level": "P4",
    "label": "Semestral Assessment 2",
    "source_prefix": "CHIJ 2022 P4 Semestral Assessment 2",
    "has_answer_key": true
  },
  "questions": [
    {
      "n": 1,
      "type_id": 1,
      "question": "65 thousands and 3 tens is the same as [?].",
      "answer0": "653",
      "answer1": "6530",
      "answer2": "65 003",
      "answer3": "65 030",
      "correct_answer": 3,
      "skill_id": 105,
      "difficulty_id": 1,
      "explanation": "65 thousands = 65 000 and 3 tens = 30. 65 000 + 30 = 65 030.",
      "hints": ["6 ten-thousands + 5 thousands = 65 000.", "3 tens = 30, so add 30 to 65 000."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q1",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q1 = option (4) = 65 030."
    },
    {
      "n": 2,
      "type_id": 1,
      "question": "Which of the following is a factor of both 27 and 60?",
      "answer0": "12",
      "answer1": "9",
      "answer2": "3",
      "answer3": "7",
      "correct_answer": 2,
      "skill_id": 113,
      "difficulty_id": 2,
      "explanation": "Factors of 27: 1, 3, 9, 27. Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60. The only common factor among the options is 3.",
      "hints": ["List the factors of each number.", "A common factor divides both numbers exactly."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q2",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q2 = option (3) = 3."
    },
    {
      "n": 3,
      "type_id": 1,
      "question": "How many one-sixths are there in 2 wholes?",
      "answer0": "1/3",
      "answer1": "6",
      "answer2": "3",
      "answer3": "12",
      "correct_answer": 3,
      "skill_id": 119,
      "difficulty_id": 1,
      "explanation": "1 whole = 6 sixths, so 2 wholes = 2 x 6 = 12 sixths.",
      "hints": ["One whole = 6 one-sixths.", "Multiply by 2 for two wholes."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q3",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q3 = option (4) = 12."
    },
    {
      "n": 4,
      "type_id": 1,
      "question": "Write 3 7/25 as a decimal.",
      "answer0": "3.725",
      "answer1": "3.7",
      "answer2": "3.28",
      "answer3": "3.25",
      "correct_answer": 2,
      "skill_id": 127,
      "difficulty_id": 2,
      "explanation": "7/25 = 28/100 = 0.28. So 3 7/25 = 3.28.",
      "hints": ["Make the denominator 100: multiply 7/25 by 4/4.", "28/100 = 0.28, then add the whole number 3."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q4",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q4 = option (3) = 3.28."
    },
    {
      "n": 5,
      "type_id": 1,
      "question": "Which of the following numbers when rounded to the nearest ten becomes 41 600?",
      "answer0": "41 666",
      "answer1": "41 596",
      "answer2": "41 606",
      "answer3": "41 664",
      "correct_answer": 1,
      "skill_id": 109,
      "difficulty_id": 2,
      "explanation": "Rounding to the nearest ten, only numbers from 41 595 to 41 604 round to 41 600. 41 596 rounds up to 41 600.",
      "hints": ["Look at the ones digit to round to the nearest ten.", "41 596: ones digit 6, rounds up the tens to give 41 600."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q5",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q5 = option (2) = 41 596."
    },
    {
      "n": 6,
      "type_id": 1,
      "question": "64 is not a multiple of [?].",
      "answer0": "6",
      "answer1": "2",
      "answer2": "8",
      "answer3": "4",
      "correct_answer": 0,
      "skill_id": 114,
      "difficulty_id": 1,
      "explanation": "64 = 2 x 32 = 8 x 8 = 4 x 16, so 64 is a multiple of 2, 8 and 4. 64 / 6 is not a whole number, so 64 is not a multiple of 6.",
      "hints": ["A multiple divides exactly with no remainder.", "Check 64 / 6 -> not a whole number."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q6",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q6 = option (1) = 6."
    },
    {
      "n": 7,
      "type_id": 1,
      "question": "A number when rounded to the nearest tenth is 24.3. What is the largest possible value of that number?",
      "answer0": "24.25",
      "answer1": "24.29",
      "answer2": "24.34",
      "answer3": "24.39",
      "correct_answer": 2,
      "skill_id": 128,
      "difficulty_id": 3,
      "explanation": "Numbers from 24.25 to 24.34 round to 24.3 (at the nearest tenth). The largest of these among the options is 24.34.",
      "hints": ["Rounding to nearest tenth: range is 24.25 up to just below 24.35.", "Pick the largest value in that range."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q7",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q7 = option (3) = 24.34."
    },
    {
      "n": 8,
      "type_id": 1,
      "question": "Dorothy's age now is between 1 and 40 and it is a multiple of 4. Next year, her age will be a multiple of 7. What is Dorothy's age next year?",
      "answer0": "21",
      "answer1": "27",
      "answer2": "28",
      "answer3": "29",
      "correct_answer": 0,
      "skill_id": 115,
      "difficulty_id": 3,
      "explanation": "Her age now is a multiple of 4 between 1 and 40. Next year (age + 1) must be a multiple of 7. Age 20 (multiple of 4) -> next year 21, which is a multiple of 7. So next year she is 21.",
      "hints": ["List multiples of 4 between 1 and 40, then add 1 to each.", "Find which result is a multiple of 7."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q8",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q8 = option (1) = 21."
    },
    {
      "n": 9,
      "type_id": 1,
      "question": "At a party, 1/4 of the children ate chocolate ice-cream, 3/8 of the children ate vanilla ice-cream. The remaining 18 children ate strawberry ice-cream. How many children ate chocolate ice-cream?",
      "answer0": "6",
      "answer1": "12",
      "answer2": "30",
      "answer3": "48",
      "correct_answer": 1,
      "skill_id": 122,
      "difficulty_id": 3,
      "explanation": "Chocolate + vanilla = 1/4 + 3/8 = 2/8 + 3/8 = 5/8. Strawberry = 1 - 5/8 = 3/8 = 18 children, so 1/8 = 6 and total = 48. Chocolate = 1/4 x 48 = 12.",
      "hints": ["Add the chocolate and vanilla fractions, then find the strawberry fraction.", "3/8 of the total = 18, so find the whole, then 1/4 of it."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q9",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q9 = option (2) = 12."
    },
    {
      "n": 10,
      "type_id": 1,
      "question": "The figure is made up of a square A with side 4 cm and a rectangle B with breadth 5 cm. What is the area of rectangle B?",
      "answer0": "16 cm²",
      "answer1": "40 cm²",
      "answer2": "60 cm²",
      "answer3": "76 cm²",
      "correct_answer": 2,
      "skill_id": 138,
      "difficulty_id": 2,
      "explanation": "Rectangle B's breadth is 5 cm. Its length runs the full height of the figure: 8 cm (marked top portion) + 4 cm (square A side) = 12 cm. Area of B = 12 x 5 = 60 cm².",
      "hints": ["The length of B is the marked 8 cm plus the 4 cm side of square A.", "Area = length x breadth = 12 x 5."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q10",
      "image_needed": true,
      "image_options": false,
      "image_file": "q10.png",
      "image_page": 5,
      "image_bbox": [0.42, 0.52, 0.66, 0.76],
      "image_loc": "centre-right of page, below the question: tall rectangle B beside small square A, with 8 cm, 5 cm and 4 cm labels",
      "notes": "Key Q10 = option (3) = 60 cm² (B length = 8 + 4 = 12 cm)."
    },
    {
      "n": 11,
      "type_id": 1,
      "question": "Paul is facing point X. He turns through an angle of 135° in the anti-clockwise direction. Which point is he facing now?",
      "answer0": "F",
      "answer1": "H",
      "answer2": "K",
      "answer3": "L",
      "correct_answer": 1,
      "skill_id": 142,
      "difficulty_id": 3,
      "explanation": "Paul faces X (South). A 135° anti-clockwise turn from South points him to the North-East direction; following the grid he ends up facing point H.",
      "hints": ["X is directly below (South of) Paul, so he starts facing South.", "Turn 135° anti-clockwise (South -> East -> North-East) and read the grid."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q11",
      "image_needed": true,
      "image_options": false,
      "image_file": "q11.png",
      "image_page": 6,
      "image_bbox": [0.30, 0.21, 0.82, 0.52],
      "image_loc": "upper-middle of page: grid map with labelled points M, F, K, H, P, L, Paul, Siti, X and a North arrow on the right",
      "notes": "8-point compass / turns skill (removed from 2026 syllabus but appears in this 2022 paper). Key Q11 = option (2) = H."
    },
    {
      "n": 12,
      "type_id": 1,
      "question": "Siti is at her starting point. She walks 2 steps to the East. She then walks 3 steps to the North. Which point is she at now?",
      "answer0": "F",
      "answer1": "H",
      "answer2": "M",
      "answer3": "P",
      "correct_answer": 3,
      "skill_id": 142,
      "difficulty_id": 3,
      "explanation": "From Siti's starting position, moving 2 steps East then 3 steps North on the grid lands on point P.",
      "hints": ["Find Siti on the grid and move 2 squares right (East).", "Then move 3 squares up (North) and read the point."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q12",
      "image_needed": true,
      "image_options": false,
      "image_file": "q12.png",
      "image_page": 6,
      "image_bbox": [0.30, 0.21, 0.82, 0.52],
      "image_loc": "same grid map as Q11 (upper-middle of page) with points M, F, K, H, P, L, Paul, Siti, X and North arrow",
      "notes": "Uses the same map figure as Q11. Key Q12 = option (4) = P."
    },
    {
      "n": 13,
      "type_id": 1,
      "question": "How many motorcycles did Mr Lee sell from May to July?",
      "answer0": "50",
      "answer1": "60",
      "answer2": "70",
      "answer3": "105",
      "correct_answer": 1,
      "skill_id": 148,
      "difficulty_id": 2,
      "explanation": "From the line graph: May = 25, June = 15, July = 20. Total = 25 + 15 + 20 = 60.",
      "hints": ["Read the value above May, June and July from the line graph.", "Add the three monthly values together."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q13",
      "image_needed": true,
      "image_options": false,
      "image_file": "q13.png",
      "image_page": 7,
      "image_bbox": [0.16, 0.17, 0.84, 0.48],
      "image_loc": "upper portion of page: line graph 'Number of motorcycles sold' (y 0-40) vs months March-July",
      "notes": "Key Q13 = option (2) = 60. Graph readings: May 25, June 15, July 20."
    },
    {
      "n": 14,
      "type_id": 2,
      "question": "What is the missing number in the number pattern below? 4649 , 4799 , 4949 , [?] , 5249",
      "answer0": "5099",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 108,
      "difficulty_id": 1,
      "explanation": "The pattern increases by 150 each time (4649 -> 4799 -> 4949). 4949 + 150 = 5099 (and 5099 + 150 = 5249, confirming).",
      "hints": ["Find the difference between consecutive terms.", "Each term increases by 150."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q14",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q14: 4949 + 150 = 5099."
    },
    {
      "n": 15,
      "type_id": 2,
      "question": "Some of the factors of 18 are 1, 2, 3 and 18. What are the other two factors of 18? [?] and [?]",
      "answer0": "9",
      "answer1": "6",
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 111,
      "difficulty_id": 1,
      "explanation": "All factors of 18 are 1, 2, 3, 6, 9 and 18. The two not yet listed are 9 and 6.",
      "hints": ["List all factor pairs of 18: 1x18, 2x9, 3x6.", "The missing factors are 6 and 9."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q15",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q15: 9 and 6 (order not graded)."
    },
    {
      "n": 16,
      "type_id": 2,
      "question": "What is the value of 5/6 + 1/3 ? Express your answer as a mixed number. [?]",
      "answer0": "1 1/6",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 121,
      "difficulty_id": 2,
      "explanation": "1/3 = 2/6. 5/6 + 2/6 = 7/6 = 1 1/6.",
      "hints": ["Make the denominators the same: 1/3 = 2/6.", "5/6 + 2/6 = 7/6, then convert to a mixed number."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q16",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q16 working: 1/3 = 2/6; 5/6 + 2/6 = 1 1/6."
    },
    {
      "n": 17,
      "type_id": 2,
      "question": "Write the decimal represented by B. [?]",
      "answer0": "0.83",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 123,
      "difficulty_id": 2,
      "explanation": "The number line from 0.8 to 0.9 is divided into 10 equal intervals of 0.01 each. B is 3 intervals past 0.8, so B = 0.8 + 0.03 = 0.83.",
      "hints": ["Each small interval between 0.8 and 0.9 is 0.01.", "Count the intervals from 0.8 to B."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q17",
      "image_needed": true,
      "image_options": false,
      "image_file": "q17.png",
      "image_page": 10,
      "image_bbox": [0.15, 0.18, 0.70, 0.28],
      "image_loc": "upper part of page: horizontal number line marked 0.8 to 0.9 with an arrow labelled B",
      "notes": "Key Q17 = 0.83."
    },
    {
      "n": 18,
      "type_id": 2,
      "question": "Arrange the following numbers from the smallest to the greatest. 0.408 , 2/5 , 0.048 [?] (smallest) , [?] , [?] (greatest)",
      "answer0": "0.048",
      "answer1": "2/5",
      "answer2": "0.408",
      "answer3": null,
      "correct_answer": null,
      "skill_id": 124,
      "difficulty_id": 2,
      "explanation": "2/5 = 0.4 = 0.400. Comparing 0.408, 0.400, 0.048: smallest 0.048, then 2/5 (0.4), then 0.408. Order: 0.048, 2/5, 0.408.",
      "hints": ["Convert 2/5 to a decimal: 2/5 = 0.4.", "Compare 0.408, 0.400 and 0.048 digit by digit."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q18",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q18: 0.048, 2/5, 0.408 (smallest to greatest)."
    },
    {
      "n": 19,
      "type_id": 2,
      "question": "PQRS is a square. Find the value of ∠x. [?]",
      "answer0": "30",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 143,
      "difficulty_id": 2,
      "explanation": "Each corner of a square is 90°, so angle SRQ = 90°. The given angle at R is 60°, so x = 90° - 60° = 30°.",
      "hints": ["A square's corner angle is 90°.", "x = 90° minus the marked 60°."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q19",
      "image_needed": true,
      "image_options": false,
      "image_file": "q19.png",
      "image_page": 10,
      "image_bbox": [0.14, 0.60, 0.36, 0.78],
      "image_loc": "lower-left of page: square PQRS with a diagonal line from R, marking 60° and x at corner R",
      "notes": "Answer in degrees. Key Q19: 90 - 60 = 30."
    },
    {
      "n": 20,
      "type_id": 2,
      "question": "At a fruit shop, apples were sold in bags of 6 only and not separately. Each bag of apples cost $4. Kelly has $19. What is the greatest number of apples that she can buy? [?]",
      "answer0": "24",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 2,
      "explanation": "$19 / $4 = 4 bags with $3 left over (4 bags cost $16). 4 bags x 6 apples = 24 apples.",
      "hints": ["How many $4 bags can $19 buy? 19 / 4 = 4 remainder 3.", "Each bag holds 6 apples: 4 x 6."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q20",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q20 working: 19/4 = 4 R3; 6 x 4 = 24 apples."
    },
    {
      "n": 21,
      "type_id": 2,
      "question": "The perimeter of a rectangle is 56 cm. Its length is 16 cm. Find the breadth of the rectangle. [?]",
      "answer0": "12",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 136,
      "difficulty_id": 2,
      "explanation": "Perimeter = 2 x (length + breadth). Half the perimeter = 56 / 2 = 28 cm = length + breadth. Breadth = 28 - 16 = 12 cm.",
      "hints": ["Length + breadth = perimeter / 2 = 28 cm.", "Subtract the length: 28 - 16."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q21",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer in cm. Key Q21: 56 - 16 - 16 = 24; 24/2 = 12."
    },
    {
      "n": 22,
      "type_id": 2,
      "question": "3 apples and 1 honeydew cost $7.17. 2 apples and 1 honeydew cost $6.27. What is the total cost of 2 apples? [?]",
      "answer0": "1.80",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 131,
      "difficulty_id": 2,
      "explanation": "The difference is exactly 1 apple: $7.17 - $6.27 = $0.90, so 1 apple = $0.90. 2 apples = $0.90 + $0.90 = $1.80.",
      "hints": ["Subtract the two totals to find the cost of one apple.", "Double it for 2 apples."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q22",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer is a dollar amount ($1.80). Key Q22: 7.17 - 6.27 = 0.90; 0.90 + 0.90 = 1.80."
    },
    {
      "n": 23,
      "type_id": 0,
      "question": "Complete the drawing by shading 2 more squares so that the dotted line is a line of symmetry.",
      "answer0": null,
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 145,
      "difficulty_id": 2,
      "explanation": "Reflect the currently shaded squares across the dotted diagonal line of symmetry; the two squares whose mirror images are not yet shaded must be shaded so the figure is symmetric about the diagonal.",
      "hints": ["Each shaded square must have a matching shaded square on the opposite side of the dotted line.", "Find the shaded squares missing their mirror partner."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q23",
      "image_needed": true,
      "image_options": false,
      "image_file": "q23.png",
      "image_page": 12,
      "image_bbox": [0.26, 0.18, 0.60, 0.43],
      "image_loc": "upper-middle of page: grid of squares with a dotted diagonal line and some squares already shaded",
      "notes": "Interactive shading/draw task - type_id 0 (skipped on insert). Answer per key: shade the two squares that complete symmetry about the diagonal dotted line."
    },
    {
      "n": 24,
      "type_id": 2,
      "question": "ABCD and CEFG are squares and MFPN is a rectangle. Given that AB = 3 cm, and NP is four times the length of AB, find the length of MG. [?]",
      "answer0": "5",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 138,
      "difficulty_id": 3,
      "explanation": "NP = 4 x AB = 4 x 3 = 12 cm, so the rectangle MFPN has height 12 cm; MF = NP = 12 cm. Square CEFG has side CE = BE - BC = 7 - 3 = 4 cm, so FG = 4 cm... actually GF = 7 cm height; MG = MF - GF = 12 - 7 = 5 cm.",
      "hints": ["NP = 4 x 3 = 12 cm, and MF equals NP.", "MG = MF - FG; FG runs the 7 cm height, so MG = 12 - 7."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q24",
      "image_needed": true,
      "image_options": false,
      "image_file": "q24.png",
      "image_page": 12,
      "image_bbox": [0.20, 0.55, 0.60, 0.80],
      "image_loc": "lower-middle of page: composite figure of squares ABCD and CEFG and rectangle MFPN, with 3 cm and 7 cm labels",
      "notes": "Answer in cm. Key Q24: 3 x 4 = 12; 12 - 7 = 5 cm."
    },
    {
      "n": 25,
      "type_id": 2,
      "question": "Ali had a rectangular piece of paper ABCD as shown in Figure 1. He folded the paper to form the shape as shown in Figure 2. Find the length of AB in Figure 1. [?]",
      "answer0": "15",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 138,
      "difficulty_id": 3,
      "explanation": "In Figure 2 the unfolded length along the top equals the original AB. The fold adds the triangular flap: AB = ZB segment (8 cm) + the folded portion. Per the key, AB = 3 + 4 + 8 = 15 cm.",
      "hints": ["Trace the original top edge AB across the folded shape.", "Add the labelled lengths: 3 cm + 4 cm + 8 cm."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q25",
      "image_needed": true,
      "image_options": false,
      "image_file": "q25.png",
      "image_page": 13,
      "image_bbox": [0.14, 0.22, 0.74, 0.58],
      "image_loc": "upper-middle of page: Figure 1 (long rectangle ABCD) above Figure 2 (L-shaped folded shape with 8 cm, 3 cm, 4 cm labels)",
      "notes": "Answer in cm. Key Q25: 3 + 4 + 8 = 15 cm."
    },
    {
      "n": 26,
      "type_id": 2,
      "question": "Jill saves $612. She saves six times as much as her brother, Tom. How much must she give Tom so that both of them have an equal amount of money? [?]",
      "answer0": "255",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Tom = $612 / 6 = $102. Together they have $612 + $102 = $714. Equal share = $714 / 2 = $357. Jill must give Tom $612 - $357 = $255.",
      "hints": ["Tom's amount = 612 / 6.", "Find the total, halve it, then subtract from Jill's amount."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q26",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer is a dollar amount ($255). Key Q26: 612/6 = 102; 612 - 102 = 510; 510/2 = $255."
    },
    {
      "n": 27,
      "type_id": 2,
      "question": "Peter and Ashraf shared some stickers equally. After Ashraf bought 46 stickers and Peter gave 112 stickers away, they had 478 stickers left. How many stickers did each of them have at first? [?]",
      "answer0": "272",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 118,
      "difficulty_id": 3,
      "explanation": "Before Ashraf's purchase and Peter's give-away, total = 478 - 46 + 112 = 544. They shared equally, so each had 544 / 2 = 272 stickers at first.",
      "hints": ["Undo the changes: subtract the 46 bought and add back the 112 given away.", "Divide the original total by 2."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q27",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key Q27: 478 - 46 = 432; 432 + 112 = 544; 544/2 = 272."
    },
    {
      "n": 28,
      "type_id": 2,
      "question": "Mary had a ribbon of 150.3 cm long. She tied some balloons on the ribbon. Each balloon was 9 cm apart from one another. (a) What is the length of the ribbon between the 2nd and 10th balloon? (b) Find the most number of balloons that could be tied on the 150.3 cm of ribbon with balloons at 9 cm apart from one another. [?] , [?]",
      "answer0": "72 cm",
      "answer1": "17",
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 129,
      "difficulty_id": 3,
      "explanation": "(a) Between the 2nd and 10th balloon there are 10 - 2 = 8 gaps of 9 cm each: 8 x 9 = 72 cm. (b) Number of gaps that fit in 150.3 cm = 150.3 / 9 = 16 remainder 6.3, so 16 gaps; balloons = 16 + 1 = 17.",
      "hints": ["Count the gaps between balloons: from 2nd to 10th is 8 gaps.", "For (b), 150.3 / 9 gives the number of gaps; add 1 for the balloons."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q28",
      "image_needed": true,
      "image_options": false,
      "image_file": "q28.png",
      "image_page": 15,
      "image_bbox": [0.12, 0.17, 0.72, 0.30],
      "image_loc": "upper part of page: ribbon with 6 balloons hanging, '9 cm' span marked, '1st' and '6th' labels",
      "notes": "Two-blank answer: (a) 72 cm, (b) 17 balloons. Key Q28: (a) 10-2=8, 8x9=72 cm; (b) 150/9=16, 16+1=17."
    },
    {
      "n": 29,
      "type_id": 2,
      "question": "Tim had a box of blue and red marbles. 5/12 of the marbles were blue. (a) What fraction of the marbles were red? (b) There were 34 fewer blue marbles than red marbles. How many marbles did Tim have altogether? [?] , [?]",
      "answer0": "7/12",
      "answer1": "204",
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 122,
      "difficulty_id": 3,
      "explanation": "(a) Red = 1 - 5/12 = 7/12. (b) Red - blue = 7/12 - 5/12 = 2/12 of the total = 34 marbles. So 1/12 = 17 and total = 17 x 12 = 204 marbles.",
      "hints": ["Red fraction = 1 - 5/12.", "The difference 2/12 of the total equals 34; find the whole."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q29",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Two-blank answer: (a) 7/12, (b) 204. Key Q29: 1 - 5/12 = 7/12; 7/12 - 5/12 = 2/12 = 34; 34/2 = 17; 17 x 12 = 204."
    },
    {
      "n": 30,
      "type_id": 2,
      "question": "A swimming pool measures 18 m by 9 m. It is surrounded by a path which is 4 m wide. What is the area of the path? [?]",
      "answer0": "280",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 138,
      "difficulty_id": 3,
      "explanation": "Pool area = 18 x 9 = 162 m². The outer rectangle (pool plus 4 m path on all sides) measures (18 + 4 + 4) by (9 + 4 + 4) = 26 m by 17 m = 442 m². Path area = 442 - 162 = 280 m².",
      "hints": ["Add 4 m on both sides to each dimension to get the outer rectangle.", "Path area = outer rectangle area - pool area."],
      "source": "CHIJ 2022 P4 Semestral Assessment 2 Q30",
      "image_needed": true,
      "image_options": false,
      "image_file": "q30.png",
      "image_page": 17,
      "image_bbox": [0.22, 0.20, 0.54, 0.40],
      "image_loc": "upper-left of page: outer rectangle (path) enclosing a shaded 'Swimming Pool' rectangle, with two '4 m' width labels",
      "notes": "Answer in m². Key Q30: 18x9=162; (18+8)x(9+8)=26x17=442; 442-162=280 cm² [printed cm² is a typo; units are m²]."
    }
  ]
}