{
  "paper": {
    "school": "CHIJ St Nicholas Girls' School",
    "year": 2022,
    "level": "P5",
    "label": "Weighted Assessment 3",
    "source_prefix": "CHIJ 2022 P5 Weighted Assessment 3",
    "has_answer_key": true
  },
  "questions": [
    {
      "n": 1,
      "type_id": 1,
      "question": "Which one of the following is two hundred and seven thousand and eleven in numerals?",
      "answer0": "2711",
      "answer1": "27 011",
      "answer2": "207 011",
      "answer3": "270 011",
      "correct_answer": 2,
      "skill_id": 149,
      "difficulty_id": 1,
      "explanation": "Two hundred and seven thousand = 207 000; plus eleven = 207 011. Answer: 207 011.",
      "hints": ["207 thousand is written 207 000.", "Add the eleven (011) at the end."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q1",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (3) = 207 011."
    },
    {
      "n": 2,
      "type_id": 1,
      "question": "Which one of the following shows \\(\\dfrac{1}{3}\\) of the figure shaded?",
      "answer0": "Figure 1",
      "answer1": "Figure 2",
      "answer2": "Figure 3",
      "answer3": "Figure 4",
      "correct_answer": 0,
      "skill_id": 157,
      "difficulty_id": 1,
      "explanation": "Figure 1 is a hexagon split into 6 equal triangles with 2 shaded = \\(\\dfrac{2}{6}=\\dfrac{1}{3}\\). The others show \\(\\dfrac{1}{4}\\), \\(\\dfrac{1}{2}\\), \\(\\dfrac{1}{3}\\)-but-unequal etc. Answer: Figure 1.",
      "hints": ["Look for shaded equal to one third of equal parts.", "Hexagon = 6 equal parts; 2 shaded is one third."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q2",
      "image_needed": true,
      "image_options": true,
      "image_file": null,
      "image_page": 2,
      "image_bbox": [0.18, 0.46, 0.82, 0.58],
      "image_loc": "row of four shaded shape figures (hexagon, circle, square, parallelogram) below Q2",
      "notes": "Key: option (1). Image-option MCQ: crop each of the 4 figures to q2_opt0..3.png."
    },
    {
      "n": 3,
      "type_id": 1,
      "question": "In the number 56.79, which digit is in the tenths place?",
      "answer0": "5",
      "answer1": "6",
      "answer2": "7",
      "answer3": "9",
      "correct_answer": 2,
      "skill_id": 158,
      "difficulty_id": 1,
      "explanation": "In 56.79 the first digit after the decimal point is the tenths place: 7. Answer: 7.",
      "hints": ["Tenths is the first digit right of the decimal point.", "56.7|9 -> tenths digit is 7."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q3",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (3) = 7."
    },
    {
      "n": 4,
      "type_id": 1,
      "question": "Colina drew some shapes: 3 circles, 5 hearts and 2 diamonds. What is the ratio of the number of diamonds to the total number of shapes?",
      "answer0": "1 : 5",
      "answer1": "1 : 4",
      "answer2": "1 : 3",
      "answer3": "1 : 2",
      "correct_answer": 0,
      "skill_id": 177,
      "difficulty_id": 1,
      "explanation": "Total shapes = 3 + 5 + 2 = 10. Diamonds = 2. Ratio 2 : 10 = 1 : 5. Answer: 1 : 5.",
      "hints": ["Count all shapes: 3 + 5 + 2 = 10.", "Diamonds : total = 2 : 10, simplify."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q4",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (1) = 1:5. Counts given in stem (3 circles, 5 hearts, 2 diamonds), so figure not required."
    },
    {
      "n": 5,
      "type_id": 1,
      "question": "What is the possible mass of a Primary 5B Mathematics Workbook?",
      "answer0": "4000 g",
      "answer1": "400 g",
      "answer2": "40 g",
      "answer3": "4 g",
      "correct_answer": 1,
      "skill_id": 184,
      "difficulty_id": 1,
      "explanation": "A workbook weighs a few hundred grams; 400 g is reasonable (4000 g = 4 kg is too heavy, 40 g and 4 g too light). Answer: 400 g.",
      "hints": ["1 kg = 1000 g; a workbook is well under 1 kg.", "Pick the realistic everyday mass."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q5",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (2) = 400 g."
    },
    {
      "n": 6,
      "type_id": 1,
      "question": "What percentage of the figure is unshaded?",
      "answer0": "5%",
      "answer1": "15%",
      "answer2": "25%",
      "answer3": "75%",
      "correct_answer": 2,
      "skill_id": 171,
      "difficulty_id": 2,
      "explanation": "The grid has 20 equal squares (4 rows x 5). 5 squares are unshaded, so unshaded = \\(\\dfrac{5}{20}=\\dfrac{1}{4}=25\\%\\). Answer: 25%.",
      "hints": ["Count the total small squares in the grid.", "Unshaded squares / total x 100%."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q6",
      "image_needed": true,
      "image_options": false,
      "image_file": "q6.png",
      "image_page": 4,
      "image_bbox": [0.35, 0.14, 0.55, 0.25],
      "image_loc": "4-by-5 grid of partly shaded squares below Q6",
      "notes": "Key: option (3) = 25%. 20-square grid, 5 unshaded."
    },
    {
      "n": 7,
      "type_id": 1,
      "question": "There are 130 white pins and 70 black pins. What percentage of the pins are black pins?",
      "answer0": "7%",
      "answer1": "35%",
      "answer2": "65%",
      "answer3": "70%",
      "correct_answer": 1,
      "skill_id": 171,
      "difficulty_id": 1,
      "explanation": "Total pins = 130 + 70 = 200. Black = \\(\\dfrac{70}{200}\\times100\\% = 35\\%\\). Answer: 35%.",
      "hints": ["Find the total number of pins first.", "Black / total x 100%."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q7",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (2) = 35%."
    },
    {
      "n": 8,
      "type_id": 1,
      "question": "A tank measuring 50 cm by 12 cm by 18 cm tall is \\(\\dfrac{4}{9}\\) filled with water. How much more water is required to fill the tank to its brim?",
      "answer0": "10 800 cm³",
      "answer1": "6000 cm³",
      "answer2": "4800 cm³",
      "answer3": "1200 cm³",
      "correct_answer": 1,
      "skill_id": 191,
      "difficulty_id": 2,
      "explanation": "Tank volume = 50 x 12 x 18 = 10 800 cm³. Empty fraction = \\(1-\\dfrac{4}{9}=\\dfrac{5}{9}\\). Water needed = \\(\\dfrac{5}{9}\\times10\\,800 = 6000\\) cm³. Answer: 6000 cm³.",
      "hints": ["Volume = length x width x height.", "Find the unfilled fraction, then that fraction of the volume."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q8",
      "image_needed": true,
      "image_options": false,
      "image_file": "q8.png",
      "image_page": 4,
      "image_bbox": [0.5, 0.72, 0.85, 0.83],
      "image_loc": "3-D cuboid tank diagram (50 cm, 12 cm, 18 cm) to the right of Q8 options",
      "notes": "Key: option (2) = 6000 cm³. Dimensions stated in stem; figure illustrative."
    },
    {
      "n": 9,
      "type_id": 1,
      "question": "Ping Chen has some gold and silver beads. The ratio of the number of gold beads to the number of silver beads is 5 : 3. She has 120 more gold beads than silver beads. How many beads does she have altogether?",
      "answer0": "480",
      "answer1": "320",
      "answer2": "300",
      "answer3": "192",
      "correct_answer": 0,
      "skill_id": 182,
      "difficulty_id": 2,
      "explanation": "Difference 5 - 3 = 2 units = 120, so 1 unit = 60. Total units = 5 + 3 = 8, so total = 8 x 60 = 480. Answer: 480.",
      "hints": ["The 120 difference equals (5 - 3) units.", "Find one unit, then multiply by total units (8)."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q9",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (1) = 480."
    },
    {
      "n": 10,
      "type_id": 1,
      "question": "The first 11 letters of a pattern are A B C D A B C D A B C ... What is the 88th letter?",
      "answer0": "A",
      "answer1": "B",
      "answer2": "C",
      "answer3": "D",
      "correct_answer": 3,
      "skill_id": 149,
      "difficulty_id": 2,
      "explanation": "The pattern repeats every 4 letters (A B C D). 88 ÷ 4 = 22 with remainder 0, so the 88th letter is the last of a block = D. Answer: D.",
      "hints": ["The block A B C D repeats every 4 positions.", "88 is a multiple of 4, so it lands on the 4th letter, D."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q10",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (4) = D. Pattern transcribed into stem; box figure not needed."
    },
    {
      "n": 11,
      "type_id": 1,
      "question": "Jason drew the top view, front view and side view of a solid figure. Which one of the following is the possible representation of the solid figure?",
      "answer0": "Solid 1",
      "answer1": "Solid 2",
      "answer2": "Solid 3",
      "answer3": "Solid 4",
      "correct_answer": 3,
      "skill_id": 187,
      "difficulty_id": 3,
      "explanation": "Matching the given top, front and side views to each option, only Solid 4's arrangement of unit cubes produces all three views. Answer: Solid 4.",
      "hints": ["Check each option against the top, front and side views.", "All three views must match for the correct solid."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q11",
      "image_needed": true,
      "image_options": true,
      "image_file": null,
      "image_page": 6,
      "image_bbox": [0.13, 0.13, 0.82, 0.24],
      "image_loc": "the Top/Front/Side view reference table at top; the four answer solids are stacked below as options (1)-(4)",
      "notes": "Key: option (4). Image-option MCQ: crop the view table to q11.png AND each unit-cube solid to q11_opt0..3.png (options stacked vertically down page 6)."
    },
    {
      "n": 12,
      "type_id": 1,
      "question": "Mrs Salleh baked some chocolate, mint and walnut cookies. \\(\\dfrac{1}{3}\\) of the cookies baked were chocolate cookies. \\(\\dfrac{1}{6}\\) of the remaining cookies were mint cookies and the rest were walnut cookies. What fraction of the cookies baked were walnut cookies?",
      "answer0": "\\(\\dfrac{5}{6}\\)",
      "answer1": "\\(\\dfrac{5}{9}\\)",
      "answer2": "\\(\\dfrac{1}{2}\\)",
      "answer3": "\\(\\dfrac{1}{9}\\)",
      "correct_answer": 1,
      "skill_id": 165,
      "difficulty_id": 2,
      "explanation": "Remaining after chocolate = \\(1-\\dfrac{1}{3}=\\dfrac{2}{3}\\). Mint = \\(\\dfrac{1}{6}\\times\\dfrac{2}{3}=\\dfrac{2}{18}=\\dfrac{1}{9}\\). Walnut = remaining minus mint = \\(\\dfrac{2}{3}-\\dfrac{1}{9}=\\dfrac{6}{9}-\\dfrac{1}{9}=\\dfrac{5}{9}\\). Answer: \\(\\dfrac{5}{9}\\).",
      "hints": ["First find the fraction remaining after chocolate.", "Walnut = remaining fraction minus mint fraction."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q12",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (2) = 5/9. Fraction options -> MCQ."
    },
    {
      "n": 13,
      "type_id": 1,
      "question": "How much longer is the sweet than the paper clip?",
      "answer0": "5.2 cm",
      "answer1": "2.8 cm",
      "answer2": "2.4 cm",
      "answer3": "2.0 cm",
      "correct_answer": 2,
      "skill_id": 184,
      "difficulty_id": 2,
      "explanation": "On the ruler the paper clip spans about 0.4 cm to 2.8 cm (length 2.4 cm) and the sweet about 2.8 cm to 7.6 cm (length 4.8 cm). Difference = 4.8 - 2.4 = 2.4 cm. Answer: 2.4 cm.",
      "hints": ["Read each object's length from the cm ruler.", "Subtract the shorter length from the longer."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q13",
      "image_needed": true,
      "image_options": false,
      "image_file": "q13.png",
      "image_page": 7,
      "image_bbox": [0.17, 0.49, 0.66, 0.65],
      "image_loc": "paper clip and sweet aligned above a 0-8 cm ruler",
      "notes": "Key: option (3) = 2.4 cm. Reading depends on the ruler image."
    },
    {
      "n": 14,
      "type_id": 1,
      "question": "This year, Indra is 8 years old. Last year, Indra's father was five times of Indra's age. How old is Indra's father this year?",
      "answer0": "35",
      "answer1": "36",
      "answer2": "40",
      "answer3": "41",
      "correct_answer": 1,
      "skill_id": 152,
      "difficulty_id": 2,
      "explanation": "Last year Indra was 8 - 1 = 7. Father last year = 5 x 7 = 35. This year father = 35 + 1 = 36. Answer: 36.",
      "hints": ["Find Indra's age last year first.", "Multiply by 5, then add 1 year to get this year's age."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q14",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (2) = 36."
    },
    {
      "n": 15,
      "type_id": 1,
      "question": "Aisha had 60 balloons at first. She used half of the total number of balloons for a party. Her mother then bought her another 12 balloons. Aisha gave all the balloons she had in the end equally to 6 friends. Which expression gives the number of balloons each friend received?",
      "answer0": "(60 ÷ 2) + 12 ÷ 6",
      "answer1": "60 ÷ (2 + 12) ÷ 6",
      "answer2": "(60 ÷ 2 + 12) ÷ 6",
      "answer3": "60 ÷ (2 + 12 ÷ 6)",
      "correct_answer": 2,
      "skill_id": 156,
      "difficulty_id": 2,
      "explanation": "Half of 60 = 60 ÷ 2 = 30 left, then +12 = 42, then shared among 6: 42 ÷ 6 = 7. The expression must compute (60 ÷ 2 + 12) first, then ÷ 6: (60 ÷ 2 + 12) ÷ 6. Answer: option (3).",
      "hints": ["Work out the order: halve, add 12, then divide by 6.", "Brackets must group (60 ÷ 2 + 12) before dividing by 6."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q15",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: option (3) = (60 ÷ 2 + 12) ÷ 6."
    },
    {
      "n": 16,
      "type_id": 2,
      "question": "Round 15 483 to the nearest hundred. [?]",
      "answer0": "15500",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 150,
      "difficulty_id": 1,
      "explanation": "The tens digit of 15 483 is 8 (>= 5), so round up the hundreds: 15 483 -> 15 500. Answer: 15 500.",
      "hints": ["Look at the tens digit (8) to decide rounding.", "8 >= 5 means round the hundreds up."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q16",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 15500. Integer answer -> FIB."
    },
    {
      "n": 17,
      "type_id": 1,
      "question": "Find the value of \\(\\dfrac{6}{10}\\times\\dfrac{4}{3}\\). Give your answer as a fraction in the simplest form.",
      "answer0": "\\(\\dfrac{4}{5}\\)",
      "answer1": "\\(\\dfrac{3}{4}\\)",
      "answer2": "\\(\\dfrac{24}{30}\\)",
      "answer3": "\\(\\dfrac{8}{15}\\)",
      "correct_answer": 0,
      "skill_id": 161,
      "difficulty_id": 2,
      "explanation": "\\(\\dfrac{6}{10}\\times\\dfrac{4}{3}=\\dfrac{24}{30}=\\dfrac{4}{5}\\). Answer: \\(\\dfrac{4}{5}\\).",
      "hints": ["Multiply numerators and denominators.", "Simplify 24/30 by dividing by 6."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q17",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 4/5. Fraction answer -> MCQ; distractors are unsimplified/common errors."
    },
    {
      "n": 18,
      "type_id": 2,
      "question": "Find the value of 1.59 × 90. [?]",
      "answer0": "143.1",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 167,
      "difficulty_id": 2,
      "explanation": "1.59 x 90 = 1.59 x 9 x 10 = 14.31 x 10 = 143.1. (Key shows \\(143\\dfrac{1}{10}\\) = 143.1.) Answer: 143.1.",
      "hints": ["Multiply 1.59 by 9 first, then by 10.", "143 1/10 written as a decimal is 143.1."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q18",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key writes 143 1/10; decimal 143.1 -> FIB."
    },
    {
      "n": 19,
      "type_id": 2,
      "question": "What is the missing number in the box?<br>3 : 13 : 9<br>= 18 : [?] : 54",
      "answer0": "78",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 181,
      "difficulty_id": 2,
      "explanation": "The ratio is multiplied by 6 (3 x 6 = 18; 9 x 6 = 54). So the missing term = 13 x 6 = 78. Answer: 78.",
      "hints": ["Find the multiplier: 18 ÷ 3 = 6.", "Multiply the middle term 13 by 6."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q19",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 78. Integer answer -> FIB."
    },
    {
      "n": 20,
      "type_id": 2,
      "question": "Fill in the blank.<br>1048 cm = [?] m",
      "answer0": "10.48",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 184,
      "difficulty_id": 1,
      "explanation": "1 m = 100 cm, so 1048 cm = 1048 ÷ 100 = 10.48 m. Answer: 10.48 m.",
      "hints": ["100 cm = 1 m.", "Divide the centimetres by 100."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q20",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 10.48 m. Decimal answer -> FIB."
    },
    {
      "n": 21,
      "type_id": 2,
      "question": "Best Buy Stationery Shop sells the following: a Ruler at $1.05 each, a Pencil at 90¢ each and an Eraser at 55¢ each. Mrs Munah bought 3 rulers, 2 pencils and 1 eraser. How much money did she spend altogether? $[?]",
      "answer0": "5.50",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 167,
      "difficulty_id": 2,
      "explanation": "Rulers: 1.05 x 3 = $3.15. Pencils: 0.90 x 2 = $1.80. Eraser: $0.55. Total = 3.15 + 1.80 + 0.55 = $5.50. Answer: $5.50.",
      "hints": ["Convert 90¢ = $0.90 and 55¢ = $0.55.", "Add the three sub-totals."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q21",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: $5.50. Price table transcribed into stem; money answer -> FIB."
    },
    {
      "n": 22,
      "type_id": 2,
      "question": "A total of 4002 children and adults were at a carnival. There were 200 more children than adults. How many children were there? [?]",
      "answer0": "2101",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 152,
      "difficulty_id": 2,
      "explanation": "Remove the extra 200: 4002 - 200 = 3802 (equal parts). Adults = 3802 ÷ 2 = 1901. Children = 1901 + 200 = 2101. Answer: 2101.",
      "hints": ["Subtract the 200 difference, then halve.", "Add the 200 back to find the children."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q22",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 2101. Integer answer -> FIB."
    },
    {
      "n": 23,
      "type_id": 2,
      "question": "At first, Stacy spent \\(\\dfrac{3}{10}\\) of her money on food and $135 on a bag. She was left with \\(\\dfrac{1}{4}\\) of her money. How much did Stacy have at first? $[?]",
      "answer0": "300",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 165,
      "difficulty_id": 3,
      "explanation": "Fraction spent on food + left = \\(\\dfrac{3}{10}+\\dfrac{1}{4}=\\dfrac{6}{20}+\\dfrac{5}{20}=\\dfrac{11}{20}\\). So the bag is the rest: \\(1-\\dfrac{11}{20}=\\dfrac{9}{20}\\) of her money = $135. 1 unit (\\(\\dfrac{1}{20}\\)) = 135 ÷ 9 = $15. Total = 20 x $15 = $300. Answer: $300.",
      "hints": ["Add the food fraction and the fraction left.", "The remaining fraction equals $135; find the whole."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q23",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key working uses 1/4=10/40, food/left combined; final $300. Money answer -> FIB."
    },
    {
      "n": 24,
      "type_id": 2,
      "question": "Joanne bought some keychains and candles for an event. The ratio of the number of keychains to the number of candles bought was 3 : 8. Joanne bought 168 keychains. How many candles did she buy? [?]",
      "answer0": "448",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 182,
      "difficulty_id": 2,
      "explanation": "3 units = 168 keychains, so 1 unit = 168 ÷ 3 = 56. Candles = 8 units = 56 x 8 = 448. Answer: 448.",
      "hints": ["168 keychains is 3 units; find 1 unit.", "Multiply by 8 for the candles."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q24",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: 448. Integer answer -> FIB."
    },
    {
      "n": 25,
      "type_id": 2,
      "question": "Triangle ABC is made up of a rectangle and 2 small triangles. AC = 10 cm and BC = 24 cm. AD = DC and CF = FB. What is the total area of the shaded part? [?] cm²",
      "answer0": "60",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 186,
      "difficulty_id": 3,
      "explanation": "DC = 10 ÷ 2 = 5 cm, CF = 24 ÷ 2 = 12 cm. The shaded part equals half of triangle ABC. Area of triangle ABC = \\(\\dfrac{1}{2}\\times24\\times10 = 120\\) cm²; shaded = \\(\\dfrac{1}{2}\\times120 = 60\\) cm². (Key: 1+1=2 parts, 10÷2=5, 24÷2=12, \\(\\dfrac{1}{2}\\times12\\times5=30\\), 30 x 2 = 60.) Answer: 60 cm².",
      "hints": ["Find DC and CF using the midpoint conditions.", "The shaded region is half of the whole triangle ABC."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q25",
      "image_needed": true,
      "image_options": false,
      "image_file": "q25.png",
      "image_page": 14,
      "image_bbox": [0.2, 0.15, 0.68, 0.30],
      "image_loc": "right-angled triangle ABC with rectangle DEFC and points A,D,C,E,F,B; shaded upper and lower triangles",
      "notes": "Key: 60 cm². Figure required for the shaded regions."
    },
    {
      "n": 26,
      "type_id": 2,
      "question": "A bank paid 1% interest at the end of each year. Mr Ong had $3000 at the start of the year in his account. He did not withdraw any of his money. How much money did he have in his account at the end of the year? $[?]",
      "answer0": "3030",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 176,
      "difficulty_id": 2,
      "explanation": "1% of $3000 = 3000 ÷ 100 = $30 interest. End of year = 3000 + 30 = $3030. Answer: $3030.",
      "hints": ["1% of $3000 is 3000 ÷ 100.", "Add the interest to the starting amount."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q26",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: $3030. Money answer -> FIB."
    },
    {
      "n": 27,
      "type_id": 2,
      "question": "Beth saves $7 every week. She wants to buy a toy doll with a usual price of $80 at a 10% discount. What is the least number of weeks she needs to save before she is able to buy the toy doll? [?]",
      "answer0": "11",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 176,
      "difficulty_id": 2,
      "explanation": "Discount = 10% of $80 = $8, so price = 80 - 8 = $72. Weeks = 72 ÷ 7 = 10 R2, so 10 weeks gives only $70; she needs 1 more week. Least = 11 weeks. Answer: 11.",
      "hints": ["Find the discounted price first ($80 minus 10%).", "Divide by $7; round up to cover the remainder."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q27",
      "image_needed": true,
      "image_options": false,
      "image_file": "q27.png",
      "image_page": 15,
      "image_bbox": [0.27, 0.14, 0.63, 0.28],
      "image_loc": "toy doll picture with a 'Discount 10%' burst and 'Usual Price: $80' label",
      "notes": "Key: 11. Usual price $80 and 10% discount given in stem; figure illustrative."
    },
    {
      "n": 28,
      "type_id": 2,
      "question": "Rectangle ABCD is made up of 3 triangles ABC, ACE and CDE. The area of rectangle ABCD is 450 cm². The length of AD is three times the length of AE. What is the area of the shaded triangle ACE? [?] cm²",
      "answer0": "75",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 186,
      "difficulty_id": 3,
      "explanation": "Triangle ACE has base AE and the same height (DC = the rectangle's width) as triangle ACD. Triangle ACD is half the rectangle = 225 cm². Since AD = 3 x AE, AE = \\(\\dfrac{1}{3}\\)AD, so area ACE = \\(\\dfrac{1}{3}\\times225 = 75\\) cm². (Key: 450 ÷ 6 = 75 cm².) Answer: 75 cm².",
      "hints": ["Triangle ACD is half the rectangle (225 cm²).", "AE is one third of AD, so ACE is one third of ACD."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q28",
      "image_needed": true,
      "image_options": false,
      "image_file": "q28.png",
      "image_page": 16,
      "image_bbox": [0.22, 0.18, 0.63, 0.33],
      "image_loc": "rectangle ABCD with point E on side AD and shaded triangle ACE",
      "notes": "Key: 75 cm². Figure required."
    },
    {
      "n": 29,
      "type_id": 0,
      "question": "At first, there were some children at a party. During lunch, some children left the party. \\(\\dfrac{3}{7}\\) of the total number of children remained at the party. After lunch, another 27 children joined the party. In the end, there were 3 more children than the number of children at first. For each statement, indicate whether it is True, False or Not possible to tell: (a) At first, there were 42 children at the party. (b) There were more girls than boys at the party in the end.",
      "answer0": null,
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 165,
      "difficulty_id": 3,
      "explanation": "Let first = N. After some left, 3/7 N remained; +27 = first + 3 means 3/7 N + 27 = N + 3, so 24 = N - 3/7 N = 4/7 N, giving N = 42. (a) TRUE (42 children at first). (b) NOT POSSIBLE TO TELL (no gender information given). Answers: (a) True, (b) Not possible to tell.",
      "hints": ["Set up 3/7 of first + 27 = first + 3 to find the first number.", "Gender split is never stated."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q29",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Interactive tick-the-box (True/False/Not possible to tell) format -> type_id 0, skipped on insert. Key: (a) True; (b) Not possible to tell."
    },
    {
      "n": 30,
      "type_id": 2,
      "question": "1 storybook and 2 similar water bottles cost $90. 2 similar storybooks cost as much as 5 similar water bottles. How much does 1 water bottle cost? $[?]",
      "answer0": "20",
      "answer1": null,
      "answer2": null,
      "answer3": null,
      "correct_answer": null,
      "skill_id": 152,
      "difficulty_id": 3,
      "explanation": "2 books = 5 bottles, so 1 book = 2.5 bottles. Then 1 book + 2 bottles = 2.5 + 2 = 4.5 bottles = $90, so 1 bottle = 90 ÷ 4.5 = $20. (Key: 5÷2=2.5, ..., 90 x 5 = 450, 450 ÷ 9 = 50, 50 x 2 = 100, 100 ÷ 5 = $20.) Answer: $20.",
      "hints": ["Express the storybook in terms of water bottles.", "Replace the book to get a total in bottles, then divide $90."],
      "source": "CHIJ 2022 P5 Weighted Assessment 3 Q30",
      "image_needed": false,
      "image_options": false,
      "image_file": null,
      "notes": "Key: $20. Money answer -> FIB."
    }
  ]
}