{
  "title": "Inverse Proportion (Direct and Inverse Variation) - Grade 8 ICSE",
  "total_questions": 60,
  "questions": [
    {
      "id": 1,
      "difficulty": "easy",
      "question": "📉 If y ∝ 1/x, then x*y = ___.",
      "options": { "A": "0", "B": "1", "C": "constant", "D": "x+y" },
      "correct_answer": "C"
    },
    {
      "id": 2,
      "difficulty": "easy",
      "question": "👷 6 workers finish a job in 10 days. 12 workers finish in ___ days.",
      "options": {
        "A": "3",
        "B": "4",
        "C": "5",
        "D": "6"
      },
      "correct_answer": "C"
    },
    {
      "id": 3,
      "difficulty": "easy",
      "question": "🚗 Speed ∝ 1/time for fixed distance. If speed doubles, time ___.",
      "options": { "A": "doubles", "B": "halves", "C": "same", "D": "triples" },
      "correct_answer": "B"
    },
    {
      "id": 4,
      "difficulty": "easy",
      "question": "🍪 8 people share cookies, each gets 6. If 12 people share equally, each gets ___.",
      "options": {
        "A": "4",
        "B": "6",
        "C": "8",
        "D": "9"
      },
      "correct_answer": "A"
    },
    {
      "id": 5,
      "difficulty": "easy",
      "question": "📦 Food stock lasts 30 days for 40 people. For 60 people, it lasts ___ days.",
      "options": {
        "A": "15",
        "B": "20",
        "C": "25",
        "D": "30"
      },
      "correct_answer": "B"
    },
    {
      "id": 6,
      "difficulty": "easy",
      "question": "⏱️ 4 taps fill a tank in 90 minutes. 6 taps fill in ___ minutes.",
      "options": {
        "A": "50",
        "B": "55",
        "C": "60",
        "D": "65"
      },
      "correct_answer": "C"
    },
    {
      "id": 7,
      "difficulty": "easy",
      "question": "📚 9 students share 36 pencils equally. If 12 students, pencils each?",
      "options": {
        "A": "2",
        "B": "3",
        "C": "4",
        "D": "5"
      },
      "correct_answer": "B"
    },
    {
      "id": 8,
      "difficulty": "easy",
      "question": "🏗️ 10 workers build a wall in 8 hours. 16 workers build in ___ hours.",
      "options": {
        "A": "4",
        "B": "5",
        "C": "6",
        "D": "7"
      },
      "correct_answer": "B"
    },
    {
      "id": 9,
      "difficulty": "easy",
      "question": "🚌 A bus covers distance in 2 hours at 60 km/hr. At 80 km/hr, time?",
      "options": {
        "A": "1.2 hours",
        "B": "1.5 hours",
        "C": "1.8 hours",
        "D": "2 hours"
      },
      "correct_answer": "B"
    },
    {
      "id": 10,
      "difficulty": "easy",
      "question": "📉 If y ∝ 1/x and y=10 when x=3, find y when x=5.",
      "options": {
        "A": "4",
        "B": "5",
        "C": "6",
        "D": "7"
      },
      "correct_answer": "C"
    },
    {
      "id": 11,
      "difficulty": "easy",
      "question": "🍕 A pizza is divided among friends. More friends means ___ slice each.",
      "options": { "A": "larger", "B": "smaller", "C": "same", "D": "none" },
      "correct_answer": "B"
    },
    {
      "id": 12,
      "difficulty": "easy",
      "question": "⏳ 5 machines make 100 items in 10 days. 10 machines make in ___ days.",
      "options": {
        "A": "4",
        "B": "5",
        "C": "6",
        "D": "7"
      },
      "correct_answer": "B"
    },
    {
      "id": 13,
      "difficulty": "easy",
      "question": "📦 If 15 boxes are needed to pack 300 books, boxes for 500 books?",
      "options": {
        "A": "20",
        "B": "22",
        "C": "24",
        "D": "25"
      },
      "correct_answer": "D"
    },
    {
      "id": 14,
      "difficulty": "easy",
      "question": "🚗 Time ∝ 1/speed. If time decreases, speed ___.",
      "options": {
        "A": "decreases",
        "B": "increases",
        "C": "same",
        "D": "zero"
      },
      "correct_answer": "B"
    },
    {
      "id": 15,
      "difficulty": "easy",
      "question": "👷 20 men complete work in 6 days. 30 men complete in ___ days.",
      "options": {
        "A": "3",
        "B": "4",
        "C": "5",
        "D": "6"
      },
      "correct_answer": "B"
    },
    {
      "id": 16,
      "difficulty": "easy",
      "question": "🍎 If 8 apples cost ₹80, 12 apples cost? (This is direct proportion, not inverse. Be careful!)",
      "options": {
        "A": "₹100",
        "B": "₹110",
        "C": "₹120",
        "D": "₹130"
      },
      "correct_answer": "C"
    },
    {
      "id": 17,
      "difficulty": "easy",
      "question": "📉 Inverse proportion: as x increases, y ___.",
      "options": {
        "A": "increases",
        "B": "decreases",
        "C": "same",
        "D": "becomes zero"
      },
      "correct_answer": "B"
    },
    {
      "id": 18,
      "difficulty": "easy",
      "question": "⏱️ 3 pumps empty tank in 8 hours. 4 pumps empty in ___ hours.",
      "options": {
        "A": "5",
        "B": "6",
        "C": "7",
        "D": "8"
      },
      "correct_answer": "B"
    },
    {
      "id": 19,
      "difficulty": "easy",
      "question": "📚 Books per shelf ∝ 1/number of shelves. More shelves, ___ books per shelf.",
      "options": { "A": "more", "B": "less", "C": "same", "D": "double" },
      "correct_answer": "B"
    },
    {
      "id": 20,
      "difficulty": "easy",
      "question": "🏗️ If 24 workers take 15 days, 36 workers take ___ days.",
      "options": {
        "A": "8",
        "B": "9",
        "C": "10",
        "D": "12"
      },
      "correct_answer": "C"
    },
    {
      "id": 21,
      "difficulty": "medium",
      "question": "📉 y ∝ 1/x. If y=12 when x=4, find y when x=6.",
      "options": {
        "A": "6",
        "B": "7",
        "C": "8",
        "D": "9"
      },
      "correct_answer": "C"
    },
    {
      "id": 22,
      "difficulty": "medium",
      "question": "👷 18 workers build a house in 50 days. How many workers to build in 30 days?",
      "options": {
        "A": "25",
        "B": "28",
        "C": "30",
        "D": "32"
      },
      "correct_answer": "C"
    },
    {
      "id": 23,
      "difficulty": "medium",
      "question": "🚗 A car travels 300 km at 60 km/hr. To cover same in 4 hours, speed needed?",
      "options": {
        "A": "70 km/hr",
        "B": "75 km/hr",
        "C": "80 km/hr",
        "D": "85 km/hr"
      },
      "correct_answer": "B"
    },
    {
      "id": 24,
      "difficulty": "medium",
      "question": "🍕 Food for 28 days for 150 people. For 200 people, lasts ___ days.",
      "options": {
        "A": "18",
        "B": "20",
        "C": "21",
        "D": "24"
      },
      "correct_answer": "C"
    },
    {
      "id": 25,
      "difficulty": "medium",
      "question": "⏱️ 10 pipes fill tank in 24 minutes. How many pipes to fill in 16 minutes?",
      "options": {
        "A": "12",
        "B": "14",
        "C": "15",
        "D": "16"
      },
      "correct_answer": "C"
    },
    {
      "id": 26,
      "difficulty": "medium",
      "question": "📦 A garrison has food for 240 soldiers for 45 days. After 15 days, 60 more soldiers join. Food lasts total ___ days.",
      "options": {
        "A": "36",
        "B": "38",
        "C": "40",
        "D": "42"
      },
      "correct_answer": "B"
    },
    {
      "id": 27,
      "difficulty": "medium",
      "question": "📉 If x and y are inversely proportional, and x=5 when y=9, find x when y=15.",
      "options": {
        "A": "2",
        "B": "3",
        "C": "4",
        "D": "5"
      },
      "correct_answer": "B"
    },
    {
      "id": 28,
      "difficulty": "medium",
      "question": "👷 12 men do work in 20 days. How many men to finish in 15 days?",
      "options": {
        "A": "14",
        "B": "15",
        "C": "16",
        "D": "18"
      },
      "correct_answer": "C"
    },
    {
      "id": 29,
      "difficulty": "medium",
      "question": "🚌 A bus covers distance in 5 hours at 40 km/hr. To cover in 4 hours, speed?",
      "options": {
        "A": "48 km/hr",
        "B": "50 km/hr",
        "C": "52 km/hr",
        "D": "55 km/hr"
      },
      "correct_answer": "B"
    },
    {
      "id": 32,
      "difficulty": "medium",
      "question": "🏗️ 15 workers build wall in 32 days. 24 workers build in ___ days.",
      "options": {
        "A": "18",
        "B": "20",
        "C": "22",
        "D": "24"
      },
      "correct_answer": "B"
    },
    {
      "id": 31,
      "difficulty": "medium",
      "question": "📉 y ∝ 1/x. x=8, y=6. Find y when x=12.",
      "options": {
        "A": "3",
        "B": "4",
        "C": "5",
        "D": "6"
      },
      "correct_answer": "B"
    },
    {
      "id": 32,
      "difficulty": "medium",
      "question": "🏗️ 15 workers build wall in 32 days. 24 workers build in ___ days.",
      "options": { "A": 18, "B": 20, "C": 22, "D": 24 },
      "correct_answer": "B"
    },
    {
      "id": 33,
      "difficulty": "medium",
      "question": "🍕 If 40 people have food for 25 days, for 50 people, food lasts ___ days.",
      "options": {
        "A": "18",
        "B": "20",
        "C": "22",
        "D": "24"
      },
      "correct_answer": "B"
    },
    {
      "id": 34,
      "difficulty": "medium",
      "question": "⏱️ 6 pumps fill tank in 14 hours. 7 pumps fill in ___ hours.",
      "options": {
        "A": "10",
        "B": "11",
        "C": "12",
        "D": "13"
      },
      "correct_answer": "C"
    },
    {
      "id": 35,
      "difficulty": "medium",
      "question": "📦 A camp has food for 120 people for 60 days. After 20 days, 30 people leave. Total days food lasts?",
      "options": {
        "A": "64",
        "B": "68",
        "C": "72",
        "D": "76"
      },
      "correct_answer": "B"
    },
    {
      "id": 36,
      "difficulty": "medium",
      "question": "📉 If xy = 72 and y ∝ 1/x, find y when x=9.",
      "options": {
        "A": "6",
        "B": "7",
        "C": "8",
        "D": "9"
      },
      "correct_answer": "C"
    },
    {
      "id": 37,
      "difficulty": "medium",
      "question": "👷 16 workers can do job in 27 days. How many workers to do in 18 days?",
      "options": {
        "A": "20",
        "B": "22",
        "C": "24",
        "D": "26"
      },
      "correct_answer": "C"
    },
    {
      "id": 38,
      "difficulty": "medium",
      "question": "🚗 To cover distance in 2.5 hours, speed 48 km/hr. To cover in 3.2 hours, speed?",
      "options": {
        "A": "36 km/hr",
        "B": "37.5 km/hr",
        "C": "40 km/hr",
        "D": "42 km/hr"
      },
      "correct_answer": "B"
    },
    {
      "id": 39,
      "difficulty": "medium",
      "question": "📚 Books packed in boxes. 24 boxes needed for 600 books. Boxes for 750 books?",
      "options": {
        "A": "28",
        "B": "30",
        "C": "32",
        "D": "36"
      },
      "correct_answer": "B"
    },
    {
      "id": 40,
      "difficulty": "medium",
      "question": "📉 If 8 men finish in 15 days, 12 men finish in ___ days.",
      "options": {
        "A": "8",
        "B": "9",
        "C": "10",
        "D": "12"
      },
      "correct_answer": "C"
    },
    {
      "id": 41,
      "difficulty": "hard",
      "question": "📉 y ∝ 1/x. When x=2.5, y=24. Find x when y=15.",
      "options": {
        "A": "3",
        "B": "3.5",
        "C": "4",
        "D": "4.5"
      },
      "correct_answer": "C"
    },
    {
      "id": 42,
      "difficulty": "hard",
      "question": "👷 24 workers build wall in 15 days. 18 workers left after 5 days. Total days to complete?",
      "options": {
        "A": "20",
        "B": "22",
        "C": "24",
        "D": "26"
      },
      "correct_answer": "D"
    },
    {
      "id": 43,
      "difficulty": "hard",
      "question": "🚗 A car travels distance at speed 45 km/hr in 8 hours. To cover same in 6 hours, speed?",
      "options": {
        "A": "55 km/hr",
        "B": "58 km/hr",
        "C": "60 km/hr",
        "D": "62 km/hr"
      },
      "correct_answer": "C"
    },
    {
      "id": 44,
      "difficulty": "hard",
      "question": "🍕 Food for 200 people for 50 days. After 20 days, 50 more people join. Total days food lasts?",
      "options": {
        "A": "40",
        "B": "42",
        "C": "44",
        "D": "46"
      },
      "correct_answer": "C"
    },
    {
      "id": 45,
      "difficulty": "hard",
      "question": "⏱️ 5 taps fill tank in 18 hours. 3 taps are added after 6 hours. Total time to fill?",
      "options": {
        "A": "12 hours",
        "B": "13.5 hours",
        "C": "14 hours",
        "D": "15 hours"
      },
      "correct_answer": "B"
    },
    {
      "id": 46,
      "difficulty": "hard",
      "question": "📉 If x and y are inversely proportional, and x=7 when y=18, find y when x=14.",
      "options": {
        "A": "7",
        "B": "8",
        "C": "9",
        "D": "10"
      },
      "correct_answer": "C"
    },
    {
      "id": 47,
      "difficulty": "hard",
      "question": "🏗️ 30 workers complete work in 28 days. After 8 days, 10 workers leave. Total days?",
      "options": {
        "A": "32",
        "B": "34",
        "C": "36",
        "D": "38"
      },
      "correct_answer": "D"
    },
    {
      "id": 48,
      "difficulty": "hard",
      "question": "🚌 A bus covers distance in 10 hours at 30 km/hr. If speed increased to 40 km/hr after 4 hours, total time?",
      "options": {
        "A": "7.5 hours",
        "B": "8 hours",
        "C": "8.5 hours",
        "D": "9 hours"
      },
      "correct_answer": "C"
    },
    {
      "id": 49,
      "difficulty": "hard",
      "question": "📚 A hostel has food for 250 students for 40 days. After 10 days, 50 students leave. After another 10 days, 50 more leave. Total days food lasts?",
      "options": {
        "A": "45",
        "B": "48",
        "C": "50",
        "D": "52"
      },
      "correct_answer": "C"
    },
    {
      "id": 50,
      "difficulty": "hard",
      "question": "📉 xy = 120. If x is doubled, y becomes ___.",
      "options": { "A": "half", "B": "double", "C": "same", "D": "triple" },
      "correct_answer": "A"
    },
    {
      "id": 51,
      "difficulty": "hard",
      "question": "👷 36 workers finish in 25 days. How many workers to finish in 20 days?",
      "options": {
        "A": "40",
        "B": "42",
        "C": "44",
        "D": "45"
      },
      "correct_answer": "D"
    },
    {
      "id": 52,
      "difficulty": "hard",
      "question": "🚗 A car covers first half at 40 km/hr, second half at 60 km/hr. Average speed?",
      "options": {
        "A": "46 km/hr",
        "B": "48 km/hr",
        "C": "50 km/hr",
        "D": "52 km/hr"
      },
      "correct_answer": "B"
    },
    {
      "id": 53,
      "difficulty": "hard",
      "question": "🍕 Food for 120 men for 100 days. After 20 days, 30 men leave. After 40 more days, 30 more leave. Total days?",
      "options": {
        "A": "110",
        "B": "115",
        "C": "120",
        "D": "125"
      },
      "correct_answer": "C"
    },
    {
      "id": 54,
      "difficulty": "hard",
      "question": "⏱️ 8 pumps fill tank in 9 hours. 3 pumps break down after 3 hours. Total time?",
      "options": {
        "A": "10 hours",
        "B": "11 hours",
        "C": "12 hours",
        "D": "13 hours"
      },
      "correct_answer": "B"
    },
    {
      "id": 55,
      "difficulty": "hard",
      "question": "📉 If 10 workers finish in 24 days, how many days if 4 workers leave after 8 days?",
      "options": {
        "A": "28",
        "B": "30",
        "C": "32",
        "D": "34"
      },
      "correct_answer": "B"
    },
    {
      "id": 56,
      "difficulty": "hard",
      "question": "🏗️ Work completed by 16 men in 12 days. 4 men left after 4 days. Total days?",
      "options": {
        "A": "14",
        "B": "15",
        "C": "16",
        "D": "17"
      },
      "correct_answer": "C"
    },
    {
      "id": 57,
      "difficulty": "hard",
      "question": "🚌 Bus travels 300 km. If speed increases by 10 km/hr, time reduces by 1 hour. Original speed?",
      "options": {
        "A": "40 km/hr",
        "B": "45 km/hr",
        "C": "50 km/hr",
        "D": "55 km/hr"
      },
      "correct_answer": "C"
    },
    {
      "id": 58,
      "difficulty": "hard",
      "question": "📚 A school has food for 400 students for 30 days. After 10 days, 100 students leave. After 10 more days, 100 more leave. Total days?",
      "options": {
        "A": "35",
        "B": "40",
        "C": "45",
        "D": "50"
      },
      "correct_answer": "B"
    },
    {
      "id": 59,
      "difficulty": "hard",
      "question": "📉 If xy = 96 and x increases by 25%, y decreases by ___%.",
      "options": {
        "A": "20%",
        "B": "25%",
        "C": "30%",
        "D": "40%"
      },
      "correct_answer": "A"
    },
    {
      "id": 60,
      "difficulty": "hard",
      "question": "👷 45 workers finish in 16 days. After 4 days, 15 workers leave. After 6 more days, 10 workers added. Total days?",
      "options": {
        "A": "20",
        "B": "21",
        "C": "22",
        "D": "23"
      },
      "correct_answer": "C"
    }
  ]
}