{
  "title": "Inverse Variation - Grade 7 ICSE",
  "total_questions": 60,
  "questions": [
    {
      "id": 1,
      "difficulty": "easy",
      "question": "👷 If 8 workers finish a job in 10 days, how many days for 10 workers? (inverse proportion)",
      "options": {
        "A": "7 days",
        "B": "8 days",
        "C": "9 days",
        "D": "10 days"
      },
      "correct_answer": "B"
    },
    {
      "id": 2,
      "difficulty": "easy",
      "question": "🚗 Speed inversely varies with time. At 60 km/h, time=4 hours. Time at 80 km/h?",
      "options": {
        "A": "2.5 hours",
        "B": "3 hours",
        "C": "3.5 hours",
        "D": "4 hours"
      },
      "correct_answer": "B"
    },
    {
      "id": 3,
      "difficulty": "easy",
      "question": "📦 12 boxes hold equal items. If each box gets 15 items, total items? (Constant total)",
      "options": { "A": "170", "B": "175", "C": "180", "D": "185" },
      "correct_answer": "C"
    },
    {
      "id": 4,
      "difficulty": "easy",
      "question": "🍫 Chocolate divided among kids. 20 kids get 3 each. If 15 kids, how many each?",
      "options": { "A": "3", "B": "4", "C": "5", "D": "6" },
      "correct_answer": "B"
    },
    {
      "id": 5,
      "difficulty": "easy",
      "question": "⏱️ y inversely varies with x. y=20 when x=5. Find y when x=10.",
      "options": { "A": "9", "B": "10", "C": "11", "D": "12" },
      "correct_answer": "B"
    },
    {
      "id": 6,
      "difficulty": "easy",
      "question": "🚌 Bus fare divided among passengers. 5 passengers pay ₹150 each. If 3 passengers, each pays?",
      "options": { "A": "₹240", "B": "₹250", "C": "₹260", "D": "₹270" },
      "correct_answer": "B"
    },
    {
      "id": 7,
      "difficulty": "easy",
      "question": "📚 Books on shelves: 6 shelves hold 10 books each. If 4 shelves, books per shelf?",
      "options": { "A": "14", "B": "15", "C": "16", "D": "17" },
      "correct_answer": "B"
    },
    {
      "id": 8,
      "difficulty": "easy",
      "question": "⛽ Fuel lasts 15 days using 20 L/day. If use 25 L/day, lasts how many days?",
      "options": {
        "A": "10 days",
        "B": "11 days",
        "C": "12 days",
        "D": "13 days"
      },
      "correct_answer": "C"
    },
    {
      "id": 9,
      "difficulty": "easy",
      "question": "🏗️ 18 workers build wall in 8 days. How many workers to finish in 6 days?",
      "options": { "A": "22", "B": "23", "C": "24", "D": "25" },
      "correct_answer": "C"
    },
    {
      "id": 10,
      "difficulty": "easy",
      "question": "🍎 Apples divided: 10 people get 6 apples each. If 12 people, each gets?",
      "options": { "A": "4", "B": "5", "C": "6", "D": "7" },
      "correct_answer": "B"
    },
    {
      "id": 11,
      "difficulty": "easy",
      "question": "📏 y inversely ∝ x. y=12 when x=4. Find x when y=6.",
      "options": { "A": "6", "B": "7", "C": "8", "D": "9" },
      "correct_answer": "C"
    },
    {
      "id": 12,
      "difficulty": "easy",
      "question": "💧 Tank fills in 30 mins with 2 taps. With 3 taps, time?",
      "options": {
        "A": "18 mins",
        "B": "19 mins",
        "C": "20 mins",
        "D": "22 mins"
      },
      "correct_answer": "C"
    },
    {
      "id": 13,
      "difficulty": "easy",
      "question": "🚚 8 trucks transport goods in 9 trips. How many trips for 12 trucks?",
      "options": { "A": "5", "B": "6", "C": "7", "D": "8" },
      "correct_answer": "B"
    },
    {
      "id": 14,
      "difficulty": "easy",
      "question": "🛠️ 5 machines make 100 parts in 4 hours. Time for 10 machines?",
      "options": {
        "A": "1.5 hours",
        "B": "2 hours",
        "C": "2.5 hours",
        "D": "3 hours"
      },
      "correct_answer": "B"
    },
    {
      "id": 15,
      "difficulty": "easy",
      "question": "📦 If 24 boxes fit in 3 racks, how many racks for 40 boxes?",
      "options": { "A": "4", "B": "5", "C": "6", "D": "7" },
      "correct_answer": "B"
    },
    {
      "id": 16,
      "difficulty": "easy",
      "question": "🍰 Cake divided: 6 slices for 4 people → slices each? If 8 people, slices each?",
      "options": {
        "A": "0.5",
        "B": "0.75",
        "C": "1",
        "D": "1.25"
      },
      "correct_answer": "B"
    },
    {
      "id": 17,
      "difficulty": "easy",
      "question": "⏳ y inversely varies: y=30 when x=2. Find y when x=5.",
      "options": { "A": "10", "B": "11", "C": "12", "D": "13" },
      "correct_answer": "C"
    },
    {
      "id": 18,
      "difficulty": "easy",
      "question": "🚲 Cycling speed inversely with time: speed 15 km/h, time=2 h. Time at 10 km/h?",
      "options": { "A": "2.5 h", "B": "3 h", "C": "3.5 h", "D": "4 h" },
      "correct_answer": "B"
    },
    {
      "id": 19,
      "difficulty": "easy",
      "question": "📚 9 shelves hold 8 books each. If 12 shelves, books per shelf?",
      "options": { "A": "5", "B": "6", "C": "7", "D": "8" },
      "correct_answer": "B"
    },
    {
      "id": 20,
      "difficulty": "easy",
      "question": "💡 Battery life inversely with power: 10 W lasts 60 h. Life at 12 W?",
      "options": { "A": "48 h", "B": "50 h", "C": "52 h", "D": "55 h" },
      "correct_answer": "B"
    },
    {
      "id": 21,
      "difficulty": "medium",
      "question": "👷 15 men finish work in 28 days. How many men to finish in 20 days?",
      "options": { "A": "20", "B": "21", "C": "22", "D": "23" },
      "correct_answer": "B"
    },
    {
      "id": 22,
      "difficulty": "medium",
      "question": "🚗 Travel time inversely with speed: 40 km/h → 6 hours. Time at 60 km/h?",
      "options": { "A": "3.5 h", "B": "4 h", "C": "4.5 h", "D": "5 h" },
      "correct_answer": "B"
    },
    {
      "id": 23,
      "difficulty": "medium",
      "question": "🍕 Pizza divided: If 8 friends get 3 slices each, how many slices each for 12 friends?",
      "options": { "A": "1.5", "B": "2", "C": "2.5", "D": "3" },
      "correct_answer": "B"
    },
    {
      "id": 24,
      "difficulty": "medium",
      "question": "📦 Storage: 18 boxes per row in 5 rows. If 15 boxes per row, rows needed?",
      "options": { "A": "5", "B": "6", "C": "7", "D": "8" },
      "correct_answer": "B"
    },
    {
      "id": 25,
      "difficulty": "medium",
      "question": "🛠️ 6 pumps empty tank in 18 hours. Time for 9 pumps?",
      "options": { "A": "10 h", "B": "11 h", "C": "12 h", "D": "13 h" },
      "correct_answer": "C"
    },
    {
      "id": 26,
      "difficulty": "medium",
      "question": "📐 y inversely varies as x. y=7 when x=9. Find y when x=21.",
      "options": { "A": "2", "B": "3", "C": "4", "D": "5" },
      "correct_answer": "B"
    },
    {
      "id": 27,
      "difficulty": "medium",
      "question": "🚌 Bus: 40 passengers pay ₹300 each. If 30 passengers, each pays?",
      "options": { "A": "₹390", "B": "₹400", "C": "₹410", "D": "₹420" },
      "correct_answer": "B"
    },
    {
      "id": 28,
      "difficulty": "medium",
      "question": "⏳ If 10 machines make product in 15 days, days for 25 machines?",
      "options": { "A": "5", "B": "6", "C": "7", "D": "8" },
      "correct_answer": "B"
    },
    {
      "id": 29,
      "difficulty": "medium",
      "question": "📚 Books: 12 shelves hold 25 books each. If 15 shelves, books per shelf?",
      "options": { "A": "18", "B": "19", "C": "20", "D": "21" },
      "correct_answer": "C"
    },
    {
      "id": 30,
      "difficulty": "medium",
      "question": "💧 Pipe fills in 45 mins. With another pipe together fill in 30 mins. Second pipe alone time? (inverse thinking)",
      "options": {
        "A": "60 min",
        "B": "75 min",
        "C": "90 min",
        "D": "100 min"
      },
      "correct_answer": "C"
    },
    {
      "id": 31,
      "difficulty": "medium",
      "question": "👷‍♂️ Work: 24 workers in 16 days. Workers needed for 12 days?",
      "options": { "A": "30", "B": "32", "C": "34", "D": "36" },
      "correct_answer": "B"
    },
    {
      "id": 32,
      "difficulty": "medium",
      "question": "🚚 5 trucks take 12 trips. Trips for 8 trucks?",
      "options": { "A": "6.5", "B": "7", "C": "7.5", "D": "8" },
      "correct_answer": "C"
    },
    {
      "id": 33,
      "difficulty": "medium",
      "question": "⛽ Car: 18 L/day lasts 20 days. If 24 L/day, lasts?",
      "options": { "A": "14", "B": "15", "C": "16", "D": "17" },
      "correct_answer": "B"
    },
    {
      "id": 34,
      "difficulty": "medium",
      "question": "📊 y ∝ 1/x, y=0.5 when x=8. Find x when y=2.",
      "options": { "A": "1", "B": "2", "C": "3", "D": "4" },
      "correct_answer": "B"
    },
    {
      "id": 35,
      "difficulty": "medium",
      "question": "🏗️ 30 labourers in 25 days. Labourers for 15 days?",
      "options": { "A": "48", "B": "50", "C": "52", "D": "54" },
      "correct_answer": "B"
    },
    {
      "id": 36,
      "difficulty": "medium",
      "question": "🍫 Chocolates: 16 kids get 10 each. If 20 kids, each gets?",
      "options": { "A": "7", "B": "8", "C": "9", "D": "10" },
      "correct_answer": "B"
    },
    {
      "id": 37,
      "difficulty": "medium",
      "question": "📦 Boxes: 6 per layer, 7 layers. If 7 per layer, layers?",
      "options": { "A": "5", "B": "6", "C": "7", "D": "8" },
      "correct_answer": "B"
    },
    {
      "id": 38,
      "difficulty": "medium",
      "question": "💡 Bulb: 60 W lasts 1200 h. Life of 75 W bulb?",
      "options": { "A": "950 h", "B": "960 h", "C": "970 h", "D": "980 h" },
      "correct_answer": "B"
    },
    {
      "id": 39,
      "difficulty": "medium",
      "question": "📐 Inverse: a=12 when b=5. Find a when b=10.",
      "options": { "A": "5", "B": "5.5", "C": "6", "D": "6.5" },
      "correct_answer": "C"
    },
    {
      "id": 40,
      "difficulty": "medium",
      "question": "🏃 Race: Speed 12 m/s time 25 s. Time at 15 m/s?",
      "options": { "A": "18 s", "B": "19 s", "C": "20 s", "D": "21 s" },
      "correct_answer": "C"
    },
    {
      "id": 41,
      "difficulty": "hard",
      "question": "👷 36 workers in 50 days. How many workers to finish 20 days earlier?",
      "options": { "A": "50", "B": "54", "C": "60", "D": "64" },
      "correct_answer": "C"
    },
    {
      "id": 42,
      "difficulty": "hard",
      "question": "🚗 Speed inversely with time: Speed up by 25%, time decreases by?",
      "options": { "A": "15%", "B": "18%", "C": "20%", "D": "22%" },
      "correct_answer": "C"
    },
    {
      "id": 43,
      "difficulty": "hard",
      "question": "📦 Stock lasts 60 days at 150 units/day. If consumption 200 units/day, lasts?",
      "options": { "A": "40", "B": "42", "C": "44", "D": "45" },
      "correct_answer": "D"
    },
    {
      "id": 44,
      "difficulty": "hard",
      "question": "📐 y varies inversely as x². y=9 when x=2. Find y when x=3.",
      "options": { "A": "3", "B": "4", "C": "5", "D": "6" },
      "correct_answer": "B"
    },
    {
      "id": 45,
      "difficulty": "hard",
      "question": "🚌 Bus: Fare per person inversely with passengers. 10 people pay ₹120 each. If fare ₹75 each, people?",
      "options": { "A": "14", "B": "15", "C": "16", "D": "17" },
      "correct_answer": "C"
    },
    {
      "id": 46,
      "difficulty": "hard",
      "question": "⏱️ Time inversely as efficiency: A takes 15 days, B 25% more efficient. B’s time?",
      "options": { "A": "11", "B": "12", "C": "13", "D": "14" },
      "correct_answer": "B"
    },
    {
      "id": 47,
      "difficulty": "hard",
      "question": "🍎 Apples: 24 boxes each 18 kg. If boxes hold 27 kg each, boxes needed?",
      "options": { "A": "14", "B": "15", "C": "16", "D": "17" },
      "correct_answer": "C"
    },
    {
      "id": 48,
      "difficulty": "hard",
      "question": "📊 y ∝ 1/√x. y=4 when x=9. Find x when y=6.",
      "options": { "A": "3", "B": "4", "C": "5", "D": "6" },
      "correct_answer": "B"
    },
    {
      "id": 49,
      "difficulty": "hard",
      "question": "🏗️ A+B do work in 12 days, A alone 20 days. B alone days? (inverse rates)",
      "options": { "A": "28", "B": "30", "C": "32", "D": "34" },
      "correct_answer": "B"
    },
    {
      "id": 50,
      "difficulty": "hard",
      "question": "⛽ Fuel: 40 L/day for 30 days. If use 25% less per day, lasts how many days?",
      "options": { "A": "38", "B": "40", "C": "42", "D": "44" },
      "correct_answer": "B"
    },
    {
      "id": 51,
      "difficulty": "hard",
      "question": "📦 Volume inversely with pressure (Boyle’s law): P=80 when V=60. Find P when V=40.",
      "options": { "A": "110", "B": "115", "C": "120", "D": "125" },
      "correct_answer": "C"
    },
    {
      "id": 52,
      "difficulty": "hard",
      "question": "👷‍♀️ Women do work in 18 days, men 50% more efficient. Men days?",
      "options": { "A": "10", "B": "11", "C": "12", "D": "13" },
      "correct_answer": "C"
    },
    {
      "id": 53,
      "difficulty": "hard",
      "question": "📐 a inversely ∝ b³. a=64 when b=1. Find b when a=8.",
      "options": { "A": "1.5", "B": "2", "C": "2.5", "D": "3" },
      "correct_answer": "B"
    },
    {
      "id": 54,
      "difficulty": "hard",
      "question": "🚚 Transport: 9 trucks in 14 days. If 2 trucks break, time for rest?",
      "options": { "A": "16", "B": "17", "C": "18", "D": "19" },
      "correct_answer": "C"
    },
    {
      "id": 55,
      "difficulty": "hard",
      "question": "💧 Pipes: 3 pipes fill in 10 h. If 1 pipe closed, time for 2?",
      "options": { "A": "14 h", "B": "15 h", "C": "16 h", "D": "18 h" },
      "correct_answer": "B"
    },
    {
      "id": 56,
      "difficulty": "hard",
      "question": "📦 Cubes: Side length inversely with ∛(number). 64 cubes of 2 cm side. If side 4 cm, how many cubes?",
      "options": { "A": "7", "B": "8", "C": "9", "D": "10" },
      "correct_answer": "B"
    },
    {
      "id": 57,
      "difficulty": "hard",
      "question": "🍰 Cake: 6 people get 200 g each. If 10 people, each gets?",
      "options": { "A": "110 g", "B": "115 g", "C": "120 g", "D": "125 g" },
      "correct_answer": "C"
    },
    {
      "id": 58,
      "difficulty": "hard",
      "question": "📊 Resistance inversely proportional to area. Area 4 mm² → 5 ohms. Area 5 mm² → resistance?",
      "options": { "A": "3.8", "B": "4", "C": "4.2", "D": "4.5" },
      "correct_answer": "B"
    },
    {
      "id": 59,
      "difficulty": "hard",
      "question": "⏳ Clock: Pendulum length inversely with (frequency)². Length 1 m → freq 1 Hz. Length 0.25 m → freq?",
      "options": { "A": "1.5", "B": "2", "C": "2.5", "D": "3" },
      "correct_answer": "B"
    },
    {
      "id": 60,
      "difficulty": "hard",
      "question": "🚗 Journey: Speed increases by 20%, time decreases by? (inverse proportion)",
      "options": { "A": "15%", "B": "16.67%", "C": "18%", "D": "20%" },
      "correct_answer": "B"
    }
  ]
}