{
  "paper": {
    "school": "Catholic High",
    "year": 2024,
    "level": "P6",
    "label": "Prelim",
    "source_prefix": "Catholic High 2024 P6 Prelim",
    "has_answer_key": true
  },
  "questions": [
    {
      "n": 1,
      "type_id": 1,
      "question": "Which of the following is the same as 5080 cm?",
      "answer0": "5 m 8 m",
      "answer1": "5 m 80 cm",
      "answer2": "50 m 8 cm",
      "answer3": "50 m 80 cm",
      "correct_answer": 3,
      "skill_id": 2,
      "difficulty_id": 1,
      "explanation": "1 m = 100 cm, so 5080 cm = 5080 ÷ 100 = 50.8 m = 50 m 80 cm. Answer: 50 m 80 cm.",
      "hints": ["1 m = 100 cm.", "5080 cm = 50 m and 80 cm left over."],
      "source": "Catholic High 2024 P6 Prelim Q1",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q1 = option 4."
    },
    {
      "n": 2,
      "type_id": 1,
      "question": "How many sevenths are there in \\(2\\dfrac{4}{7}\\)?",
      "answer0": "13",
      "answer1": "15",
      "answer2": "18",
      "answer3": "24",
      "correct_answer": 2,
      "skill_id": 206,
      "difficulty_id": 1,
      "explanation": "\\(2\\dfrac{4}{7} = \\dfrac{2\\times 7 + 4}{7} = \\dfrac{18}{7}\\), which is 18 sevenths. Answer: 18.",
      "hints": ["Convert the mixed number to an improper fraction with denominator 7.", "2 wholes = 14 sevenths; add the extra 4 sevenths."],
      "source": "Catholic High 2024 P6 Prelim Q2",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q2 = option 3."
    },
    {
      "n": 3,
      "type_id": 1,
      "question": "What is a possible volume of hot water that fills a disposable cup completely?",
      "answer0": "32 m³",
      "answer1": "32 cm³",
      "answer2": "320 m³",
      "answer3": "320 cm³",
      "correct_answer": 3,
      "skill_id": 229,
      "difficulty_id": 1,
      "explanation": "A disposable cup holds a small everyday volume. 32 cm³ is too little and m³ is far too large; a realistic cup holds about 320 cm³. Answer: 320 cm³.",
      "hints": ["A cubic metre is the size of a large box — far too big for a cup.", "A cup holds a few hundred cm³."],
      "source": "Catholic High 2024 P6 Prelim Q3",
      "image_needed": true,
      "image_options": false,
      "image_file": "q3.png",
      "image_page": 2,
      "image_bbox": [0.34, 0.55, 0.66, 0.74],
      "image_loc": "drawing of a hand holding a labelled disposable cup, middle of page below the question",
      "notes": "Answer key Q3 = option 4. Figure is illustrative."
    },
    {
      "n": 4,
      "type_id": 1,
      "question": "The figure shows a cube.<br>Which of the following is a net of the cube?",
      "answer0": "Net 1",
      "answer1": "Net 2",
      "answer2": "Net 3",
      "answer3": "Net 4",
      "correct_answer": 1,
      "skill_id": 229,
      "difficulty_id": 2,
      "explanation": "Folding each net up, only net 2 (the staircase of three pairs of squares) folds into a closed cube with all six faces; the others either overlap a face or leave a gap. Answer: Net 2.",
      "hints": ["A cube net must have exactly 6 squares that fold without overlapping.", "Mentally fold each option and check no face is missing or doubled."],
      "source": "Catholic High 2024 P6 Prelim Q4",
      "image_needed": true,
      "image_options": true,
      "image_file": null,
      "image_page": 3,
      "image_bbox": [0.20, 0.21, 0.46, 0.66],
      "image_loc": "small cube figure near top, and four candidate net diagrams (1)-(4) down the left-middle of the page",
      "notes": "Answer key Q4 = option 2. Options are pictures of nets — crop each option to q4_opt0..3.png."
    },
    {
      "n": 5,
      "type_id": 1,
      "question": "Which two lines are perpendicular to each other?",
      "answer0": "AB and BC",
      "answer1": "BC and AD",
      "answer2": "CD and AB",
      "answer3": "CD and AD",
      "correct_answer": 0,
      "skill_id": 230,
      "difficulty_id": 2,
      "explanation": "On the square grid, lines AB and BC meet at B at a right angle (the slopes are negative reciprocals). Answer: AB and BC.",
      "hints": ["Perpendicular lines meet at 90°.", "Use the grid squares to compare the steepness of each pair of lines."],
      "source": "Catholic High 2024 P6 Prelim Q5",
      "image_needed": true,
      "image_options": false,
      "image_file": "q5.png",
      "image_page": 4,
      "image_bbox": [0.31, 0.13, 0.62, 0.35],
      "image_loc": "square grid with quadrilateral ABCD drawn on it, top of page below the question",
      "notes": "Answer key Q5 = option 1."
    },
    {
      "n": 6,
      "type_id": 1,
      "question": "What is the mass of the packet of flour?",
      "answer0": "760 g",
      "answer1": "800 g",
      "answer2": "850 g",
      "answer3": "950 g",
      "correct_answer": 2,
      "skill_id": 461,
      "difficulty_id": 1,
      "explanation": "The scale's needle points between 750 g and the next major mark; reading the dial gives 850 g. Answer: 850 g.",
      "hints": ["The dial goes 0, 250, 500, 750 g going round.", "Read where the needle points between the marked values."],
      "source": "Catholic High 2024 P6 Prelim Q6",
      "image_needed": true,
      "image_options": false,
      "image_file": "q6.png",
      "image_page": 4,
      "image_bbox": [0.34, 0.50, 0.66, 0.80],
      "image_loc": "kitchen weighing scale with a packet of flour on the pan and a circular dial, middle of page",
      "notes": "Answer key Q6 = option 3."
    },
    {
      "n": 7,
      "type_id": 1,
      "question": "Which of the following decimal is the smallest?",
      "answer0": "0.110",
      "answer1": "0.200",
      "answer2": "0.003",
      "answer3": "0.040",
      "correct_answer": 2,
      "skill_id": 2,
      "difficulty_id": 1,
      "explanation": "Compare to 3 decimal places: 0.110, 0.200, 0.003, 0.040. The smallest is 0.003. Answer: 0.003.",
      "hints": ["Line up the decimal points and compare digit by digit.", "0.003 has 0 tenths and 0 hundredths."],
      "source": "Catholic High 2024 P6 Prelim Q7",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q7 = option 3."
    },
    {
      "n": 8,
      "type_id": 1,
      "question": "The line graph shows the amount of rainfall over 5 months. The amount of rainfall is not shown on the scale.<br>From which month to the next was the increase in rainfall the greatest?",
      "answer0": "From Jan to Feb",
      "answer1": "From Feb to Mar",
      "answer2": "From Mar to Apr",
      "answer3": "From Apr to May",
      "correct_answer": 0,
      "skill_id": 461,
      "difficulty_id": 1,
      "explanation": "An increase needs the line to go up. Jan→Feb rises by many units, Feb→Mar rises by fewer, Mar→Apr falls, Apr→May rises but less than Jan→Feb. The steepest upward step is Jan to Feb. Answer: From Jan to Feb.",
      "hints": ["Only consider months where the line goes UP.", "The greatest increase is the steepest upward segment."],
      "source": "Catholic High 2024 P6 Prelim Q8",
      "image_needed": true,
      "image_options": false,
      "image_file": "q8.png",
      "image_page": 5,
      "image_bbox": [0.30, 0.32, 0.76, 0.56],
      "image_loc": "line graph of amount of rainfall (cm) vs months Jan-May, middle of page",
      "notes": "Answer key Q8 = option 1."
    },
    {
      "n": 9,
      "type_id": 1,
      "question": "Charles and Denny started running a marathon at 5.20 a.m. Charles was 20 minutes slower than Denny who completed the marathon at 9.05 a.m. How long did Charles take to complete the marathon?",
      "answer0": "3 h 25 min",
      "answer1": "4 h 5 min",
      "answer2": "3 h 55 min",
      "answer3": "4 h 35 min",
      "correct_answer": 1,
      "skill_id": 461,
      "difficulty_id": 2,
      "explanation": "Denny's time = 5.20 a.m. to 9.05 a.m. = 3 h 45 min. Charles was 20 min slower: 3 h 45 min + 20 min = 4 h 5 min. Answer: 4 h 5 min.",
      "hints": ["First find Denny's time from 5.20 a.m. to 9.05 a.m.", "Charles took 20 minutes MORE than Denny."],
      "source": "Catholic High 2024 P6 Prelim Q9",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q9 = option 2."
    },
    {
      "n": 10,
      "type_id": 1,
      "question": "In a school, the ratio of the number of boys to the number of girls is 1 : 2. The pie charts show the different ways boys and girls go to school.<br>What is the ratio of the number of boys who walk to school to the number of girls who walk to school?",
      "answer0": "4 : 5",
      "answer1": "5 : 4",
      "answer2": "8 : 5",
      "answer3": "5 : 8",
      "correct_answer": 3,
      "skill_id": 214,
      "difficulty_id": 3,
      "explanation": "Take boys = 1 unit, girls = 2 units. Boys who walk = 100% − 55% − (private) ; from the chart boys walk 25% (the remaining sector), so boys walk = 25% × 1 = 0.25 units. Girls walk = 20% × 2 = 0.40 units. Ratio = 0.25 : 0.40 = 25 : 40 = 5 : 8. Answer: 5 : 8.",
      "hints": ["Let boys = 1 unit and girls = 2 units.", "Multiply each group's walk percentage by its number of units, then simplify the ratio."],
      "source": "Catholic High 2024 P6 Prelim Q10",
      "image_needed": true,
      "image_options": false,
      "image_file": "q10.png",
      "image_page": 6,
      "image_bbox": [0.28, 0.34, 0.74, 0.54],
      "image_loc": "two pie charts labelled Boys and Girls showing Public transport / Walk / Private vehicles sectors, middle of page",
      "notes": "Answer key Q10 = option 4. Boys: Public transport 55%, Walk 25% (rest), Private vehicles 20%. Girls: Walk 20%."
    },
    {
      "n": 11,
      "type_id": 1,
      "question": "In the figure, ABCD is a square. AD = DF and ∠ADF = 58°. Find ∠BEF.",
      "answer0": "71°",
      "answer1": "74°",
      "answer2": "106°",
      "answer3": "109°",
      "correct_answer": 1,
      "skill_id": 230,
      "difficulty_id": 3,
      "explanation": "Triangle ADF is isosceles (AD = DF) with ∠ADF = 58°, so ∠DAF = ∠DFA = (180° − 58°) ÷ 2 = 61°. ∠DAB = 90° (square), so ∠FAB = 90° − 61° = 29°. In triangle ABE (with diagonal/line through B), ∠BEF is the exterior angle. Using the angles, ∠BEF = 74°. Answer: 74°.",
      "hints": ["Triangle ADF is isosceles because AD = DF.", "Use the square's 90° corner and the angle sum of a triangle to chase the angle at E."],
      "source": "Catholic High 2024 P6 Prelim Q11",
      "image_needed": true,
      "image_options": false,
      "image_file": "q11.png",
      "image_page": 7,
      "image_bbox": [0.33, 0.13, 0.62, 0.32],
      "image_loc": "square ABCD with lines from D and A meeting at E and F, 58° marked at D, top of page",
      "notes": "Answer key Q11 = option 2 (74°)."
    },
    {
      "n": 12,
      "type_id": 1,
      "question": "Ivan had 30 fewer sweets than Peggy at first. After he gave some of his sweets to Peggy, he was left with 28 sweets. Peggy had 3 times as many sweets as Ivan in the end. How many sweets did Ivan give to Peggy?",
      "answer0": "13",
      "answer1": "26",
      "answer2": "27",
      "answer3": "54",
      "correct_answer": 0,
      "skill_id": 241,
      "difficulty_id": 3,
      "explanation": "In the end Ivan had 28, so Peggy had 3 × 28 = 84. Total sweets stay the same: 28 + 84 = 112. At first Ivan had x and Peggy had x + 30, so 2x + 30 = 112, x = 41. Ivan gave away 41 − 28 = 13 sweets. Answer: 13.",
      "hints": ["The total number of sweets does not change when Ivan gives some to Peggy.", "End: Ivan 28, Peggy 3×28 = 84. Work back to Ivan's starting amount."],
      "source": "Catholic High 2024 P6 Prelim Q12",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q12 = option 1 (13)."
    },
    {
      "n": 13,
      "type_id": 1,
      "question": "A rectangular paper is folded along the dotted line AB to form a second figure (with angles c and d as marked).<br>Which of the following statement(s) is/are true?<br>Statement A: ∠c + ∠d = 90°<br>Statement B: The area of the first figure is less than the area of the second figure.<br>Statement C: Both figures have at least a line of symmetry.",
      "answer0": "A only",
      "answer1": "B only",
      "answer2": "A and C only",
      "answer3": "B and C only",
      "correct_answer": 2,
      "skill_id": 230,
      "difficulty_id": 3,
      "explanation": "Folding does not change area, so the unfolded rectangle (Figure 1) has a larger area than the folded Figure 2, making Statement B false. The fold creates angles c and d that add to 90° (Statement A true). The rectangle has lines of symmetry and the folded figure also has a line of symmetry (Statement C true). True statements: A and C only.",
      "hints": ["Folding overlaps part of the paper, so the visible area gets smaller — check Statement B.", "A rectangle has lines of symmetry; consider whether the folded shape does too."],
      "source": "Catholic High 2024 P6 Prelim Q13",
      "image_needed": true,
      "image_options": false,
      "image_file": "q13.png",
      "image_page": 8,
      "image_bbox": [0.18, 0.16, 0.84, 0.31],
      "image_loc": "'Before folding' rectangle with diagonal dotted line A-B and 'After folding' figure with angles c and d marked, top of page",
      "notes": "Answer key Q13 = option 3 (A and C only)."
    },
    {
      "n": 14,
      "type_id": 1,
      "question": "The figure is made up of two identical quarter circles and a square. The length of the square is 7 cm. What is the perimeter of the figure? \\(\\left(\\text{Take } \\pi = \\dfrac{22}{7}\\right)\\)",
      "answer0": "39 cm",
      "answer1": "50 cm",
      "answer2": "72 cm",
      "answer3": "126 cm",
      "correct_answer": 1,
      "skill_id": 222,
      "difficulty_id": 2,
      "explanation": "Each quarter circle has radius 7 cm, arc = \\(\\dfrac{1}{4}\\times 2\\pi r = \\dfrac{1}{4}\\times 2\\times\\dfrac{22}{7}\\times 7 = 11\\) cm. Two arcs = 22 cm. The perimeter also includes the bottom of the square (7 cm) and the two radii sticking out on the base sides; the outer straight edges total 7 + 7 + 7 = 21 cm, but only the bottom (7 cm) plus the two outer radii (7 + 7 = 14 cm) are on the boundary, giving straight parts = 28 cm. Perimeter = 22 + 28 = 50 cm. Answer: 50 cm.",
      "hints": ["Each quarter-circle arc = \\(\\dfrac{1}{4}\\) of a full circle of radius 7 cm.", "Add the curved arcs to the straight edges that lie on the outline."],
      "source": "Catholic High 2024 P6 Prelim Q14",
      "image_needed": true,
      "image_options": false,
      "image_file": "q14.png",
      "image_page": 8,
      "image_bbox": [0.26, 0.62, 0.66, 0.76],
      "image_loc": "dome-shaped figure (two quarter circles flanking a central square gap, 7 cm marked across the top), middle of page",
      "notes": "Answer key Q14 = option 2 (50 cm)."
    },
    {
      "n": 15,
      "type_id": 1,
      "question": "Mrs Lim bought some pears and oranges and packed them into two bags. \\(\\dfrac{3}{4}\\) of the fruits were in bag A and the rest in bag B. \\(\\dfrac{4}{9}\\) of the fruits in bag A were pears. \\(\\dfrac{1}{2}\\) of the fruits bought were oranges. What fraction of the fruits in bag B were pears?",
      "answer0": "\\(\\dfrac{1}{4}\\)",
      "answer1": "\\(\\dfrac{1}{6}\\)",
      "answer2": "\\(\\dfrac{5}{9}\\)",
      "answer3": "\\(\\dfrac{2}{3}\\)",
      "correct_answer": 3,
      "skill_id": 209,
      "difficulty_id": 3,
      "explanation": "Take 36 fruits total. Bag A = \\(\\dfrac{3}{4}\\times 36 = 27\\); bag B = 9. Pears in A = \\(\\dfrac{4}{9}\\times 27 = 12\\). Total pears = total − oranges = 36 − \\(\\dfrac{1}{2}\\times 36\\) = 36 − 18 = 18. Pears in B = 18 − 12 = 6. Fraction of bag B that are pears = \\(\\dfrac{6}{9} = \\dfrac{2}{3}\\). Answer: \\(\\dfrac{2}{3}\\).",
      "hints": ["Pick a convenient total (a multiple of 4 and 9, e.g. 36).", "Pears in B = total pears − pears in A, then divide by the number in bag B."],
      "source": "Catholic High 2024 P6 Prelim Q15",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q15 = option 4 (2/3). MCQ because the answer is a fraction."
    },
    {
      "n": 16,
      "type_id": 2,
      "question": "Round 12 976 to the nearest hundred.<br>[?]",
      "answer0": "13000",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 2,
      "difficulty_id": 1,
      "explanation": "The tens digit of 12 976 is 7, so round up: the hundreds become 13 000. Answer: 13 000.",
      "hints": ["Look at the tens digit (7) to decide whether to round up.", "12 976 is between 12 900 and 13 000; it is closer to 13 000."],
      "source": "Catholic High 2024 P6 Prelim Q16",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q16 = 13000."
    },
    {
      "n": 17,
      "type_id": 2,
      "question": "Find the value of \\(2.34 \\times 60\\).<br>[?]",
      "answer0": "140.4",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 2,
      "difficulty_id": 1,
      "explanation": "2.34 × 60 = 2.34 × 6 × 10 = 14.04 × 10 = 140.4. Answer: 140.4.",
      "hints": ["2.34 × 6 = 14.04.", "Then multiply by 10."],
      "source": "Catholic High 2024 P6 Prelim Q17",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q17 = 140.4."
    },
    {
      "n": 18,
      "type_id": 1,
      "question": "Find the value of \\(\\dfrac{4}{7} \\div 14\\). Give your answer as a fraction in the simplest form.",
      "answer0": "\\(\\dfrac{2}{49}\\)",
      "answer1": "\\(\\dfrac{4}{98}\\)",
      "answer2": "\\(\\dfrac{1}{14}\\)",
      "answer3": "\\(\\dfrac{8}{7}\\)",
      "correct_answer": 0,
      "skill_id": 206,
      "difficulty_id": 2,
      "explanation": "\\(\\dfrac{4}{7} \\div 14 = \\dfrac{4}{7} \\times \\dfrac{1}{14} = \\dfrac{4}{98} = \\dfrac{2}{49}\\). Answer: \\(\\dfrac{2}{49}\\).",
      "hints": ["Dividing by 14 is the same as multiplying by \\(\\dfrac{1}{14}\\).", "Simplify \\(\\dfrac{4}{98}\\) by dividing top and bottom by 2."],
      "source": "Catholic High 2024 P6 Prelim Q18",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q18 = 2/49. Made MCQ because the answer is a fraction (FIB must be integer/decimal only)."
    },
    {
      "n": 19,
      "type_id": 2,
      "question": "Find the value of \\(\\dfrac{10w}{5} - w + 1\\) when \\(w = 4\\).<br>[?]",
      "answer0": "5",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 240,
      "difficulty_id": 2,
      "explanation": "Substitute w = 4: \\(\\dfrac{10\\times 4}{5} - 4 + 1 = \\dfrac{40}{5} - 4 + 1 = 8 - 4 + 1 = 5\\). Answer: 5.",
      "hints": ["Replace every w with 4.", "\\(\\dfrac{10\\times 4}{5} = 8\\), then do 8 − 4 + 1."],
      "source": "Catholic High 2024 P6 Prelim Q19",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q19 = 5."
    },
    {
      "n": 20,
      "type_id": 2,
      "question": "Write down all the common factors of 8 and 12.<br>[?], [?], [?]",
      "answer0": "1",
      "answer1": "2",
      "answer2": "4",
      "answer3": null,
      "correct_answer": null,
      "skill_id": 2,
      "difficulty_id": 1,
      "explanation": "Factors of 8: 1, 2, 4, 8. Factors of 12: 1, 2, 3, 4, 6, 12. Common factors: 1, 2, 4. Answer: 1, 2, 4.",
      "hints": ["List the factors of 8 and the factors of 12 separately.", "Pick the numbers that appear in both lists."],
      "source": "Catholic High 2024 P6 Prelim Q20",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q20 = 1, 2, 4. FIB with three blanks (one per common factor) in ascending order."
    },
    {
      "n": 21,
      "type_id": 2,
      "question": "Use all the digits 6, 5, 0, 8 to form<br>(a) the greatest multiple of 5. [?]<br>(b) the number closest to 6000. [?]",
      "answer0": "8650",
      "answer1": "6058",
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 2,
      "difficulty_id": 2,
      "explanation": "(a) A multiple of 5 ends in 0 or 5. For the greatest, end in 0 and put the largest digits first: 8650. (b) Numbers near 6000 must start with 6; the smallest remaining arrangement is 6058, which is closest to 6000. Answers: (a) 8650, (b) 6058.",
      "hints": ["A multiple of 5 ends in 0 or 5; to be greatest, end in 0 and arrange the rest in descending order.", "To be closest to 6000, start with 6 and make the rest as small as possible."],
      "source": "Catholic High 2024 P6 Prelim Q21",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q21a = 8650, Q21b = 6058. Two-part FIB, one blank per part."
    },
    {
      "n": 22,
      "type_id": 2,
      "question": "Jessie had a total of thirty 20¢ and 10¢ coins. She exchanged all the 10¢ coins for 20¢ coins and had a total of seventeen 20¢ coins after the exchange. How many 10¢ coins did she have at first?<br>[?]",
      "answer0": "26",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 241,
      "difficulty_id": 3,
      "explanation": "Value of 17 twenty-cent coins = 17 × 20¢ = $3.40. Original 30 coins, if all were 20¢, would be $6, but the value is only $3.40, a shortfall caused by the 10¢ coins. Each 10¢ coin is 10¢ short of a 20¢ coin; shortfall = $6 − $3.40 = $2.60, so number of 10¢ coins = $2.60 ÷ 10¢ = 26. Answer: 26.",
      "hints": ["After exchange the total value is 17 × 20¢ = $3.40 (value is unchanged by exchanging).", "Compare with 30 × 20¢ = $6; the difference is made up of the 10¢ coins."],
      "source": "Catholic High 2024 P6 Prelim Q22",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q22 = 26."
    },
    {
      "n": 23,
      "type_id": 2,
      "question": "Find the area of the shaded triangle.<br>[?] cm²",
      "answer0": "240",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 464,
      "difficulty_id": 2,
      "explanation": "The shaded triangle's base = 42 − 10 = 32 cm and its height = 15 cm. Area = \\(\\dfrac{1}{2}\\times 32 \\times 15 = 240\\) cm². Answer: 240 cm².",
      "hints": ["The base of the shaded triangle is the long side minus the 10 cm part: 42 − 10.", "Area of a triangle = \\(\\dfrac{1}{2}\\times\\) base \\(\\times\\) height."],
      "source": "Catholic High 2024 P6 Prelim Q23",
      "image_needed": true,
      "image_options": false,
      "image_file": "q23.png",
      "image_page": 14,
      "image_bbox": [0.26, 0.11, 0.62, 0.26],
      "image_loc": "shaded triangle with height 15 cm, a 10 cm base segment and total base 42 cm marked, top of page",
      "notes": "Answer key Q23 = 240 cm². Unit cm² is fixed in the stem; answer is the number 240."
    },
    {
      "n": 24,
      "type_id": 1,
      "question": "A rhombus ABCD is on a square grid. A square PQRS is drawn (using line RS) so that it has the same perimeter as ABCD.<br>What fraction of the area of rhombus ABCD is the area of square PQRS?",
      "answer0": "\\(1\\dfrac{1}{12}\\)",
      "answer1": "\\(\\dfrac{12}{13}\\)",
      "answer2": "\\(\\dfrac{11}{12}\\)",
      "answer3": "\\(1\\dfrac{1}{13}\\)",
      "correct_answer": 0,
      "skill_id": 223,
      "difficulty_id": 3,
      "explanation": "Rhombus ABCD has diagonals of 4 and 6 grid units, so its area = \\(\\dfrac{1}{2}\\times 4 \\times 6 = 12\\) square units (4 right-triangles of \\(\\dfrac{1}{2}\\times 2\\times 3\\)). The equal-perimeter square PQRS has area 13 square units. Fraction = \\(\\dfrac{13}{12} = 1\\dfrac{1}{12}\\). Answer: \\(1\\dfrac{1}{12}\\).",
      "hints": ["Find the rhombus area from its diagonals on the grid.", "PQRS has the same perimeter; compare the two areas as a fraction."],
      "source": "Catholic High 2024 P6 Prelim Q24",
      "image_needed": true,
      "image_options": false,
      "image_file": "q24.png",
      "image_page": 14,
      "image_bbox": [0.30, 0.50, 0.62, 0.78],
      "image_loc": "square grid with rhombus ABCD on the left and line RS lower right, middle-lower of page",
      "notes": "Answer key: Q24(b) = 13/12 = 1 1/12 (printed working: 4×½×2×3=12, 12+1=13, 13/12). Part (a) is a draw-on-grid task (interactive) and is omitted; only part (b) is captured. Made MCQ because the answer is a mixed number."
    },
    {
      "n": 25,
      "type_id": 2,
      "question": "In 1 minute, Machine A can pack 5 boxes of cookies while Machine B can pack 2 boxes of cookies. Both machines started packing at 12.50 a.m. At what time will both machines pack 175 boxes of cookies in total? Leave your answer in 24-hour clock.<br>[?]",
      "answer0": "0115",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 241,
      "difficulty_id": 2,
      "explanation": "Together the machines pack 5 + 2 = 7 boxes per minute. Time for 175 boxes = 175 ÷ 7 = 25 minutes. 12.50 a.m. + 25 min = 1.15 a.m. = 0115 in 24-hour clock. Answer: 0115.",
      "hints": ["Add the two rates: 5 + 2 boxes per minute.", "175 ÷ 7 = 25 minutes; add 25 minutes to 12.50 a.m."],
      "source": "Catholic High 2024 P6 Prelim Q25",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q25 = 0115. Answer is a 24-hour clock time entered as 0115."
    },
    {
      "n": 26,
      "type_id": 2,
      "question": "The airmail rates to a country are: First 20 g costs ____________ ¢; every additional 10 g or less costs 12¢. Quentin sent a letter that weighed 33 g. He paid 56¢. How much did Quentin pay for the first 20 g of the letter?<br>[?] ¢",
      "answer0": "32",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 241,
      "difficulty_id": 2,
      "explanation": "Weight above 20 g = 33 − 20 = 13 g, which is 2 blocks of '10 g or less' (10 g + 3 g). Additional charge = 2 × 12¢ = 24¢. First 20 g charge = 56¢ − 24¢ = 32¢. Answer: 32¢.",
      "hints": ["13 g over the first 20 g counts as 2 blocks of 'every additional 10 g or less'.", "Subtract the additional charge from the total 56¢."],
      "source": "Catholic High 2024 P6 Prelim Q26",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q26 = 32¢. The '? ¢' table cell is shown with underscores; the real answer blank is the cost of the first 20 g."
    },
    {
      "n": 27,
      "type_id": 2,
      "question": "Gregory glued 9 unit cubes together to form a solid. He then glued more unit cubes to the solid to form a cube. What was the least number of unit cubes used by Gregory?<br>[?]",
      "answer0": "64",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 229,
      "difficulty_id": 2,
      "explanation": "The solid fits inside a 4×4×4 cube (the smallest cube big enough to contain it). A full cube needs 4³ = 64 unit cubes. Answer: 64.",
      "hints": ["A solid cube has the same number of cubes along each edge.", "The smallest cube that contains this solid is 4 by 4 by 4."],
      "source": "Catholic High 2024 P6 Prelim Q27",
      "image_needed": true,
      "image_options": false,
      "image_file": "q27.png",
      "image_page": 16,
      "image_bbox": [0.30, 0.12, 0.66, 0.36],
      "image_loc": "isometric drawing of the 9-unit-cube solid with Top/Front/Side view arrows, top of page",
      "notes": "Answer key Q27(b) = 64 (4³). Part (a) is a draw-the-top-view-on-the-grid task (interactive) and is omitted; only part (b), the numeric answer, is captured."
    },
    {
      "n": 28,
      "type_id": 2,
      "question": "40 pupils helped to sell packets of popcorn at a school carnival. Each pupil was given 6 packets of popcorn to sell. Some pupils did not turn up, so each pupil present had to sell 2 more packets of popcorn to meet the required sale. How many pupils did not turn up?<br>[?]",
      "answer0": "10",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 241,
      "difficulty_id": 3,
      "explanation": "Total packets = 40 × 6 = 240. Each present pupil sold 6 + 2 = 8 packets, so pupils present = 240 ÷ 8 = 30. Pupils who did not turn up = 40 − 30 = 10. Answer: 10.",
      "hints": ["First find the total packets: 40 × 6.", "Each present pupil now sells 8; divide the total by 8 to get pupils present."],
      "source": "Catholic High 2024 P6 Prelim Q28",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q28 = 10."
    },
    {
      "n": 29,
      "type_id": 2,
      "question": "A box contains beads of three different colours. \\(\\dfrac{3}{5}\\) of the beads are red and the rest are blue beads and green beads. The ratio of the number of blue beads to that of green beads is 2 : 3. What percentage of the beads is blue?<br>[?] %",
      "answer0": "16",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 213,
      "difficulty_id": 3,
      "explanation": "Non-red beads = \\(1 - \\dfrac{3}{5} = \\dfrac{2}{5}\\) of the total. Blue : green = 2 : 3, so blue = \\(\\dfrac{2}{5}\\) of the non-red beads = \\(\\dfrac{2}{5}\\times\\dfrac{2}{5} = \\dfrac{4}{25}\\) of all beads = 16%. Answer: 16%.",
      "hints": ["Find the fraction of beads that are NOT red.", "Blue is \\(\\dfrac{2}{5}\\) of that fraction; convert to a percentage."],
      "source": "Catholic High 2024 P6 Prelim Q29",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q29 = 16%. Answer is the number 16 (% fixed in stem)."
    },
    {
      "n": 30,
      "type_id": 2,
      "question": "A bakery had a number of cakes for sale. After selling 42 cakes in the morning and \\(\\dfrac{4}{9}\\) of the remainder in the afternoon, it was left with \\(\\dfrac{1}{3}\\) of the cakes. How many cakes were left?<br>[?]",
      "answer0": "35",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 209,
      "difficulty_id": 3,
      "explanation": "After selling \\(\\dfrac{4}{9}\\) of the remainder, \\(\\dfrac{5}{9}\\) of the remainder is left, and this equals \\(\\dfrac{1}{3}\\) of the original. So \\(\\dfrac{1}{3} = \\dfrac{5}{15}\\) of the original corresponds to \\(\\dfrac{5}{9}\\) of the remainder, meaning the remainder = \\(\\dfrac{1}{3}\\div\\dfrac{5}{9}\\) of original. Using the printed working: \\(1-\\dfrac{4}{9}=\\dfrac{5}{9}\\); \\(\\dfrac{1}{3}=\\dfrac{5}{15}\\); 15 − 9 = 6 units = the 42 sold, so 1 unit = 7; cakes left = \\(\\dfrac{1}{3}\\) of original. With 42 ÷ 6 × 5 = 35 cakes left. Answer: 35.",
      "hints": ["\\(\\dfrac{5}{9}\\) of the remainder is left, and that equals \\(\\dfrac{1}{3}\\) of the original.", "Make the denominators match (5/15 and 5/9) so the 42 sold corresponds to the difference in units."],
      "source": "Catholic High 2024 P6 Prelim Q30",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Answer key Q30 working: 1-4/9=5/9, 1/3=5/15, 15-9=6, 42÷6×5=35. Answer = 35 cakes left."
    }
  ]
}
