{
  "title": "Volume of Cylinder - Grade 9 CBSE",
  "total_questions": 100,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "What is formula for volume of cylinder?", "options": {"A": "πr²", "B": "πr²h", "C": "2πrh", "D": "2πr(r+h)"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "Volume of cylinder with r=7 cm, h=10 cm is:", "options": {"A": "140π cm³", "B": "245π cm³", "C": "490π cm³", "D": "700π cm³"}, "correct_answer": "C"},
    {"id": 3, "difficulty": "easy", "question": "If r=14 cm, h=15 cm, volume =", "options": {"A": "2940π cm³", "B": "3920π cm³", "C": "4410π cm³", "D": "5880π cm³"}, "correct_answer": "A"},
    {"id": 4, "difficulty": "easy", "question": "Cylinder: r=3.5 cm, h=10 cm. Volume:", "options": {"A": "35π cm³", "B": "122.5π cm³", "C": "245π cm³", "D": "350π cm³"}, "correct_answer": "B"},
    {"id": 5, "difficulty": "easy", "question": "Volume of cylinder with diameter 14 cm, height 20 cm:", "options": {"A": "980π cm³", "B": "1960π cm³", "C": "3920π cm³", "D": "7840π cm³"}, "correct_answer": "A"},
    {"id": 6, "difficulty": "easy", "question": "If volume=1540 cm³, h=10 cm, find r (π=22/7).", "options": {"A": "5 cm", "B": "6 cm", "C": "7 cm", "D": "8 cm"}, "correct_answer": "C"},
    {"id": 7, "difficulty": "easy", "question": "Cylinder: r=10 cm, h=21 cm. Volume:", "options": {"A": "2100π cm³", "B": "4200π cm³", "C": "6300π cm³", "D": "8400π cm³"}, "correct_answer": "A"},
    {"id": 8, "difficulty": "easy", "question": "Volume of cylinder diameter 20 cm, height 14 cm:", "options": {"A": "1400π cm³", "B": "2800π cm³", "C": "4200π cm³", "D": "5600π cm³"}, "correct_answer": "A"},
    {"id": 9, "difficulty": "easy", "question": "If volume=2464 cm³, r=7 cm, find h (π=22/7).", "options": {"A": "12 cm", "B": "14 cm", "C": "16 cm", "D": "18 cm"}, "correct_answer": "C"},
    {"id": 10, "difficulty": "easy", "question": "Cylinder: r=4.2 cm, h=15 cm. Volume:", "options": {"A": "88.2π cm³", "B": "176.4π cm³", "C": "264.6π cm³", "D": "352.8π cm³"}, "correct_answer": "C"},
    {"id": 11, "difficulty": "easy", "question": "Volume of cylinder r=5 cm, h=8 cm:", "options": {"A": "40π cm³", "B": "80π cm³", "C": "200π cm³", "D": "400π cm³"}, "correct_answer": "C"},
    {"id": 12, "difficulty": "easy", "question": "If volume=1386 cm³, h=9 cm, find r (π=22/7).", "options": {"A": "6 cm", "B": "7 cm", "C": "8 cm", "D": "9 cm"}, "correct_answer": "B"},
    {"id": 13, "difficulty": "easy", "question": "Cylinder: diameter 28 cm, h=15 cm. Volume:", "options": {"A": "2940π cm³", "B": "5880π cm³", "C": "8820π cm³", "D": "11760π cm³"}, "correct_answer": "A"},
    {"id": 14, "difficulty": "easy", "question": "Volume of cylinder r=6 cm, h=10.5 cm:", "options": {"A": "63π cm³", "B": "126π cm³", "C": "252π cm³", "D": "378π cm³"}, "correct_answer": "D"},
    {"id": 15, "difficulty": "easy", "question": "If volume=2156 cm³, r=7 cm, find h (π=22/7).", "options": {"A": "12 cm", "B": "13 cm", "C": "14 cm", "D": "15 cm"}, "correct_answer": "C"},
    {"id": 16, "difficulty": "easy", "question": "Cylinder: r=8.4 cm, h=25 cm. Volume:", "options": {"A": "210π cm³", "B": "420π cm³", "C": "1764π cm³", "D": "3528π cm³"}, "correct_answer": "C"},
    {"id": 17, "difficulty": "easy", "question": "Volume of cylinder diameter 42 cm, h=20 cm:", "options": {"A": "1764π cm³", "B": "3528π cm³", "C": "4410π cm³", "D": "8820π cm³"}, "correct_answer": "C"},
    {"id": 18, "difficulty": "easy", "question": "If volume=3234 cm³, h=21 cm, find r (π=22/7).", "options": {"A": "6 cm", "B": "7 cm", "C": "8 cm", "D": "9 cm"}, "correct_answer": "B"},
    {"id": 19, "difficulty": "easy", "question": "Cylinder: r=9.1 cm, h=30 cm. Volume:", "options": {"A": "273π cm³", "B": "546π cm³", "C": "819π cm³", "D": "1092π cm³"}, "correct_answer": "C"},
    {"id": 20, "difficulty": "easy", "question": "Volume of cylinder r=10.5 cm, h=16 cm:", "options": {"A": "168π cm³", "B": "336π cm³", "C": "1764π cm³", "D": "3528π cm³"}, "correct_answer": "C"},

    {"id": 21, "difficulty": "medium", "question": "Cylinder has volume 1617 cm³, height 10.5 cm. Find radius (π=22/7).", "options": {"A": "6 cm", "B": "6.5 cm", "C": "7 cm", "D": "7.5 cm"}, "correct_answer": "C"},
    {"id": 22, "difficulty": "medium", "question": "Volume of cylinder is 9856 cm³. If radius is 14 cm, find height (π=22/7).", "options": {"A": "14 cm", "B": "15 cm", "C": "16 cm", "D": "17 cm"}, "correct_answer": "C"},
    {"id": 23, "difficulty": "medium", "question": "Cylinder: r=8.75 cm, h=12.8 cm. Volume:", "options": {"A": "98π cm³", "B": "245π cm³", "C": "392π cm³", "D": "784π cm³"}, "correct_answer": "C"},
    {"id": 24, "difficulty": "medium", "question": "If volume of cylinder is 5544 cm³ and height is 18 cm, find radius (π=22/7).", "options": {"A": "8 cm", "B": "9 cm", "C": "10 cm", "D": "11 cm"}, "correct_answer": "C"},
    {"id": 25, "difficulty": "medium", "question": "Cylinder has diameter 35 cm and volume 13475 cm³. Find height (π=22/7).", "options": {"A": "12 cm", "B": "13 cm", "C": "14 cm", "D": "15 cm"}, "correct_answer": "C"},
    {"id": 26, "difficulty": "medium", "question": "Volume of cylinder is 8316 cm³. If radius is 10.5 cm, find height (π=22/7).", "options": {"A": "22 cm", "B": "23 cm", "C": "24 cm", "D": "25 cm"}, "correct_answer": "C"},
    {"id": 27, "difficulty": "medium", "question": "Cylinder: r=12.6 cm, h=15.4 cm. Volume:", "options": {"A": "1524.6π cm³", "B": "1944.8π cm³", "C": "2441.9π cm³", "D": "3056.4π cm³"}, "correct_answer": "C"},
    {"id": 28, "difficulty": "medium", "question": "If volume is 11088 cm³ and height is 28 cm, find radius (π=22/7).", "options": {"A": "10 cm", "B": "11 cm", "C": "12 cm", "D": "13 cm"}, "correct_answer": "C"},
    {"id": 29, "difficulty": "medium", "question": "Cylinder has volume 19404 cm³ and radius 14 cm. Find height (π=22/7).", "options": {"A": "29 cm", "B": "30 cm", "C": "31 cm", "D": "32 cm"}, "correct_answer": "C"},
    {"id": 30, "difficulty": "medium", "question": "Volume of cylinder diameter 42 cm is 14553 cm³. Find height (π=22/7).", "options": {"A": "9.5 cm", "B": "10 cm", "C": "10.5 cm", "D": "11 cm"}, "correct_answer": "C"},
    {"id": 31, "difficulty": "medium", "question": "Cylinder: r=15.75 cm, h=18.2 cm. Volume:", "options": {"A": "2835π cm³", "B": "3969π cm³", "C": "4536π cm³", "D": "5670π cm³"}, "correct_answer": "C"},
    {"id": 32, "difficulty": "medium", "question": "If volume is 16632 cm³ and radius is 12 cm, find height (π=22/7).", "options": {"A": "35 cm", "B": "36 cm", "C": "37 cm", "D": "38 cm"}, "correct_answer": "C"},
    {"id": 33, "difficulty": "medium", "question": "Cylinder has volume 22176 cm³, height 32 cm. Find radius (π=22/7).", "options": {"A": "13 cm", "B": "14 cm", "C": "15 cm", "D": "16 cm"}, "correct_answer": "C"},
    {"id": 34, "difficulty": "medium", "question": "Volume of cylinder r=16.8 cm, h=22.4 cm:", "options": {"A": "4032π cm³", "B": "5376π cm³", "C": "6048π cm³", "D": "8064π cm³"}, "correct_answer": "D"},
    {"id": 35, "difficulty": "medium", "question": "If volume is 25872 cm³ and height is 42 cm, find radius (π=22/7).", "options": {"A": "12 cm", "B": "13 cm", "C": "14 cm", "D": "15 cm"}, "correct_answer": "C"},
    {"id": 36, "difficulty": "medium", "question": "Cylinder: diameter 56 cm, volume 68992 cm³. Height (π=22/7):", "options": {"A": "26 cm", "B": "27 cm", "C": "28 cm", "D": "29 cm"}, "correct_answer": "C"},
    {"id": 37, "difficulty": "medium", "question": "Volume of cylinder r=18.9 cm, h=25.2 cm:", "options": {"A": "4536π cm³", "B": "5670π cm³", "C": "6804π cm³", "D": "9072π cm³"}, "correct_answer": "D"},
    {"id": 38, "difficulty": "medium", "question": "If volume is 30492 cm³ and radius is 14 cm, find height (π=22/7).", "options": {"A": "47 cm", "B": "48 cm", "C": "49 cm", "D": "50 cm"}, "correct_answer": "C"},
    {"id": 39, "difficulty": "medium", "question": "Cylinder has volume 38808 cm³, height 63 cm. Find radius (π=22/7).", "options": {"A": "12 cm", "B": "13 cm", "C": "14 cm", "D": "15 cm"}, "correct_answer": "C"},
    {"id": 40, "difficulty": "medium", "question": "Volume of cylinder diameter 70 cm is 134750 cm³. Height (π=22/7):", "options": {"A": "33 cm", "B": "34 cm", "C": "35 cm", "D": "36 cm"}, "correct_answer": "C"},
    {"id": 41, "difficulty": "medium", "question": "Cylinder: r=21.7 cm, h=28.6 cm. Volume:", "options": {"A": "5929π cm³", "B": "11858π cm³", "C": "17787π cm³", "D": "23716π cm³"}, "correct_answer": "C"},
    {"id": 42, "difficulty": "medium", "question": "If volume is 41580 cm³ and height is 45 cm, find radius (π=22/7).", "options": {"A": "13 cm", "B": "14 cm", "C": "15 cm", "D": "16 cm"}, "correct_answer": "B"},
    {"id": 43, "difficulty": "medium", "question": "Cylinder has volume 55440 cm³, radius 20 cm. Find height (π=22/7).", "options": {"A": "42 cm", "B": "43 cm", "C": "44 cm", "D": "45 cm"}, "correct_answer": "C"},
    {"id": 44, "difficulty": "medium", "question": "Volume of cylinder r=24.5 cm, h=32.8 cm:", "options": {"A": "7840π cm³", "B": "9800π cm³", "C": "11760π cm³", "D": "15680π cm³"}, "correct_answer": "D"},
    {"id": 45, "difficulty": "medium", "question": "If volume is 66528 cm³ and radius is 18 cm, find height (π=22/7).", "options": {"A": "64 cm", "B": "65 cm", "C": "66 cm", "D": "67 cm"}, "correct_answer": "C"},
    {"id": 46, "difficulty": "medium", "question": "Cylinder: diameter 84 cm, volume 349272 cm³. Height (π=22/7):", "options": {"A": "61 cm", "B": "62 cm", "C": "63 cm", "D": "64 cm"}, "correct_answer": "C"},
    {"id": 47, "difficulty": "medium", "question": "Volume of cylinder r=27.3 cm, h=36.4 cm:", "options": {"A": "10164π cm³", "B": "13552π cm³", "C": "20328π cm³", "D": "27104π cm³"}, "correct_answer": "D"},
    {"id": 48, "difficulty": "medium", "question": "If volume is 77616 cm³ and height is 56 cm, find radius (π=22/7).", "options": {"A": "19 cm", "B": "20 cm", "C": "21 cm", "D": "22 cm"}, "correct_answer": "C"},
    {"id": 49, "difficulty": "medium", "question": "Cylinder has volume 99792 cm³, radius 21 cm. Find height (π=22/7).", "options": {"A": "70 cm", "B": "71 cm", "C": "72 cm", "D": "73 cm"}, "correct_answer": "C"},
    {"id": 50, "difficulty": "medium", "question": "Volume of cylinder diameter 98 cm is 711480 cm³. Height (π=22/7):", "options": {"A": "92 cm", "B": "93 cm", "C": "94 cm", "D": "95 cm"}, "correct_answer": "D"},
    {"id": 51, "difficulty": "medium", "question": "Cylinder: r=30.8 cm, h=41.6 cm. Volume:", "options": {"A": "13184π cm³", "B": "19776π cm³", "C": "26368π cm³", "D": "39552π cm³"}, "correct_answer": "D"},
    {"id": 52, "difficulty": "medium", "question": "If volume is 121968 cm³ and height is 72 cm, find radius (π=22/7).", "options": {"A": "22 cm", "B": "23 cm", "C": "24 cm", "D": "25 cm"}, "correct_answer": "B"},
    {"id": 53, "difficulty": "medium", "question": "Cylinder has volume 149688 cm³, radius 24 cm. Find height (π=22/7).", "options": {"A": "81 cm", "B": "82 cm", "C": "83 cm", "D": "84 cm"}, "correct_answer": "C"},
    {"id": 54, "difficulty": "medium", "question": "Volume of cylinder r=34.3 cm, h=46.2 cm:", "options": {"A": "16170π cm³", "B": "24255π cm³", "C": "32340π cm³", "D": "48510π cm³"}, "correct_answer": "D"},
    {"id": 55, "difficulty": "medium", "question": "If volume is 172480 cm³ and radius is 25 cm, find height (π=22/7).", "options": {"A": "86 cm", "B": "87 cm", "C": "88 cm", "D": "89 cm"}, "correct_answer": "C"},
    {"id": 56, "difficulty": "medium", "question": "Cylinder: diameter 112 cm, volume 1103872 cm³. Height (π=22/7):", "options": {"A": "109 cm", "B": "110 cm", "C": "111 cm", "D": "112 cm"}, "correct_answer": "D"},
    {"id": 57, "difficulty": "medium", "question": "Volume of cylinder r=38.5 cm, h=52.8 cm:", "options": {"A": "20328π cm³", "B": "30492π cm³", "C": "40656π cm³", "D": "60984π cm³"}, "correct_answer": "D"},
    {"id": 58, "difficulty": "medium", "question": "If volume is 221760 cm³ and height is 90 cm, find radius (π=22/7).", "options": {"A": "26 cm", "B": "27 cm", "C": "28 cm", "D": "29 cm"}, "correct_answer": "C"},
    {"id": 59, "difficulty": "medium", "question": "Cylinder has volume 266112 cm³, radius 28 cm. Find height (π=22/7).", "options": {"A": "106 cm", "B": "107 cm", "C": "108 cm", "D": "109 cm"}, "correct_answer": "C"},
    {"id": 60, "difficulty": "medium", "question": "Volume of cylinder diameter 126 cm is 1494108 cm³. Height (π=22/7):", "options": {"A": "117 cm", "B": "118 cm", "C": "119 cm", "D": "120 cm"}, "correct_answer": "D"},
    {"id": 61, "difficulty": "medium", "question": "Cylinder: r=43.4 cm, h=59.2 cm. Volume:", "options": {"A": "25600π cm³", "B": "38400π cm³", "C": "51200π cm³", "D": "76800π cm³"}, "correct_answer": "D"},
    {"id": 62, "difficulty": "medium", "question": "If volume is 332640 cm³ and radius is 30 cm, find height (π=22/7).", "options": {"A": "116 cm", "B": "117 cm", "C": "118 cm", "D": "119 cm"}, "correct_answer": "C"},
    {"id": 63, "difficulty": "medium", "question": "Cylinder has volume 399168 cm³, height 112 cm. Find radius (π=22/7).", "options": {"A": "32 cm", "B": "33 cm", "C": "34 cm", "D": "35 cm"}, "correct_answer": "C"},
    {"id": 64, "difficulty": "medium", "question": "Volume of cylinder r=48.3 cm, h=66.4 cm:", "options": {"A": "32256π cm³", "B": "48384π cm³", "C": "64512π cm³", "D": "96768π cm³"}, "correct_answer": "D"},
    {"id": 65, "difficulty": "medium", "question": "If volume is 498960 cm³ and height is 135 cm, find radius (π=22/7).", "options": {"A": "33 cm", "B": "34 cm", "C": "35 cm", "D": "36 cm"}, "correct_answer": "B"},
    {"id": 66, "difficulty": "medium", "question": "Cylinder: diameter 140 cm, volume 2156000 cm³. Height (π=22/7):", "options": {"A": "138 cm", "B": "139 cm", "C": "140 cm", "D": "141 cm"}, "correct_answer": "C"},
    {"id": 67, "difficulty": "medium", "question": "Volume of cylinder r=53.9 cm, h=74.8 cm:", "options": {"A": "42924π cm³", "B": "64386π cm³", "C": "85848π cm³", "D": "128772π cm³"}, "correct_answer": "D"},
    {"id": 68, "difficulty": "medium", "question": "If volume is 665280 cm³ and radius is 35 cm, find height (π=22/7).", "options": {"A": "170 cm", "B": "171 cm", "C": "172 cm", "D": "173 cm"}, "correct_answer": "C"},
    {"id": 69, "difficulty": "medium", "question": "Cylinder has volume 798336 cm³, height 144 cm. Find radius (π=22/7).", "options": {"A": "41 cm", "B": "42 cm", "C": "43 cm", "D": "44 cm"}, "correct_answer": "B"},
    {"id": 70, "difficulty": "medium", "question": "Volume of cylinder diameter 154 cm is 2929996 cm³. Height (π=22/7):", "options": {"A": "155 cm", "B": "156 cm", "C": "157 cm", "D": "158 cm"}, "correct_answer": "D"},
    {"id": 71, "difficulty": "medium", "question": "Cylinder: r=60.2 cm, h=83.6 cm. Volume:", "options": {"A": "50500π cm³", "B": "75750π cm³", "C": "101000π cm³", "D": "151500π cm³"}, "correct_answer": "D"},
    {"id": 72, "difficulty": "medium", "question": "If volume is 931392 cm³ and height is 168 cm, find radius (π=22/7).", "options": {"A": "41 cm", "B": "42 cm", "C": "43 cm", "D": "44 cm"}, "correct_answer": "B"},
    {"id": 73, "difficulty": "medium", "question": "Cylinder has volume 1197504 cm³, radius 42 cm. Find height (π=22/7).", "options": {"A": "215 cm", "B": "216 cm", "C": "217 cm", "D": "218 cm"}, "correct_answer": "B"},
    {"id": 74, "difficulty": "medium", "question": "Volume of cylinder r=67.9 cm, h=94.8 cm:", "options": {"A": "64896π cm³", "B": "97344π cm³", "C": "129792π cm³", "D": "194688π cm³"}, "correct_answer": "D"},
    {"id": 75, "difficulty": "medium", "question": "If volume is 1333584 cm³ and radius is 46 cm, find height (π=22/7).", "options": {"A": "199 cm", "B": "200 cm", "C": "201 cm", "D": "202 cm"}, "correct_answer": "C"},
    {"id": 76, "difficulty": "medium", "question": "Cylinder: diameter 168 cm, volume 4188384 cm³. Height (π=22/7):", "options": {"A": "187 cm", "B": "188 cm", "C": "189 cm", "D": "190 cm"}, "correct_answer": "C"},
    {"id": 77, "difficulty": "medium", "question": "Volume of cylinder r=76.3 cm, h=107.2 cm:", "options": {"A": "83600π cm³", "B": "125400π cm³", "C": "167200π cm³", "D": "250800π cm³"}, "correct_answer": "D"},
    {"id": 78, "difficulty": "medium", "question": "If volume is 1862784 cm³ and height is 216 cm, find radius (π=22/7).", "options": {"A": "51 cm", "B": "52 cm", "C": "53 cm", "D": "54 cm"}, "correct_answer": "B"},
    {"id": 79, "difficulty": "medium", "question": "Cylinder has volume 2395008 cm³, height 224 cm. Find radius (π=22/7).", "options": {"A": "58 cm", "B": "59 cm", "C": "60 cm", "D": "61 cm"}, "correct_answer": "B"},
    {"id": 80, "difficulty": "medium", "question": "Volume of cylinder diameter 182 cm is 5855850 cm³. Height (π=22/7):", "options": {"A": "223 cm", "B": "224 cm", "C": "225 cm", "D": "226 cm"}, "correct_answer": "C"},

    {"id": 81, "difficulty": "hard", "question": "Two cylinders have volumes in ratio 27:64. If their heights are in ratio 3:4, find ratio of their radii.", "options": {"A": "3:4", "B": "4:5", "C": "2:3", "D": "3:2"}, "correct_answer": "A"},
    {"id": 82, "difficulty": "hard", "question": "Cylinder melted to form cone of same radius and height 27 cm. If cylinder height was 9 cm, find original cylinder volume.", "options": {"A": "243π cm³", "B": "324π cm³", "C": "486π cm³", "D": "729π cm³"}, "correct_answer": "D"},
    {"id": 83, "difficulty": "hard", "question": "If radius of cylinder increased by 20% and height decreased by 10%, find % change in volume.", "options": {"A": "29.6% increase", "B": "30.4% increase", "C": "31.2% increase", "D": "32.8% increase"}, "correct_answer": "A"},
    {"id": 84, "difficulty": "hard", "question": "Cylinder has curved surface area 1320 cm² and height 21 cm. Find volume (π=22/7).", "options": {"A": "4620 cm³", "B": "5280 cm³", "C": "5940 cm³", "D": "6600 cm³"}, "correct_answer": "D"},
    {"id": 85, "difficulty": "hard", "question": "Three cylinders of radii 3cm, 4cm, 5cm and heights 10cm, 12cm, 14cm melted to form single cylinder of radius 7cm. Find height.", "options": {"A": "10 cm", "B": "12 cm", "C": "14 cm", "D": "16 cm"}, "correct_answer": "C"},
    {"id": 86, "difficulty": "hard", "question": "If volume of cylinder is 2156 cm³ and total surface area is 1188 cm², find radius (π=22/7).", "options": {"A": "6 cm", "B": "7 cm", "C": "8 cm", "D": "9 cm"}, "correct_answer": "B"},
    {"id": 87, "difficulty": "hard", "question": "Cylinder radius doubled and height halved. What is ratio of new volume to original?", "options": {"A": "1:1", "B": "1:2", "C": "2:1", "D": "4:1"}, "correct_answer": "C"},
    {"id": 88, "difficulty": "hard", "question": "Cylinder has volume 1232 cm³. If height increased by 100% and radius decreased by 50%, new volume?", "options": {"A": "308 cm³", "B": "616 cm³", "C": "924 cm³", "D": "1232 cm³"}, "correct_answer": "B"},
    {"id": 89, "difficulty": "hard", "question": "Two cylinders have equal volumes. One has radius 6 cm and height 7 cm, other has radius 7 cm. Find its height.", "options": {"A": "36/7 cm", "B": "6 cm", "C": "42/7 cm", "D": "7 cm"}, "correct_answer": "A"},
    {"id": 90, "difficulty": "hard", "question": "Cylinder of height 28 cm melted to form sphere of radius 21 cm. Find cylinder radius (π=22/7).", "options": {"A": "14 cm", "B": "21 cm", "C": "28 cm", "D": "35 cm"}, "correct_answer": "B"},
    {"id": 91, "difficulty": "hard", "question": "If cylinder radius increased by 50% and height decreased by 20%, volume change?", "options": {"A": "70% increase", "B": "80% increase", "C": "90% increase", "D": "100% increase"}, "correct_answer": "B"},
    {"id": 92, "difficulty": "hard", "question": "Cylinder has total surface area 2992 cm² and radius 14 cm. Find volume (π=22/7).", "options": {"A": "8624 cm³", "B": "9856 cm³", "C": "11088 cm³", "D": "12320 cm³"}, "correct_answer": "B"},
    {"id": 93, "difficulty": "hard", "question": "Water in cylindrical tank radius 10.5 m, height 4 m transferred to cuboidal tank 11m×7m×3m. How much water overflows?", "options": {"A": "0 m³", "B": "21 m³", "C": "42 m³", "D": "63 m³"}, "correct_answer": "C"},
    {"id": 94, "difficulty": "hard", "question": "Cylinder volume is 5 times cone volume. Both have same radius and height. If cone height 12 cm, find cylinder height.", "options": {"A": "12 cm", "B": "24 cm", "C": "36 cm", "D": "60 cm"}, "correct_answer": "C"},
    {"id": 95, "difficulty": "hard", "question": "If ratio of radii of two cylinders is 2:3 and ratio of volumes 4:9, find ratio of heights.", "options": {"A": "1:1", "B": "2:3", "C": "3:2", "D": "4:9"}, "correct_answer": "A"},
    {"id": 96, "difficulty": "hard", "question": "Cylinder of radius 7 cm and height 14 cm melted to form cones of radius 3.5 cm, height 7 cm. How many cones?", "options": {"A": "12", "B": "18", "C": "24", "D": "36"}, "correct_answer": "C"},
    {"id": 97, "difficulty": "hard", "question": "If curved surface area of cylinder 1760 cm² and height 20 cm, find volume (π=22/7).", "options": {"A": "12320 cm³", "B": "15400 cm³", "C": "18480 cm³", "D": "21560 cm³"}, "correct_answer": "B"},
    {"id": 98, "difficulty": "hard", "question": "Cylinder height increased by 10% and radius decreased by 10%. Find % change in volume.", "options": {"A": "8.9% decrease", "B": "10.9% decrease", "C": "12.9% decrease", "D": "14.9% decrease"}, "correct_answer": "A"},
    {"id": 99, "difficulty": "hard", "question": "Two cylinders have equal curved surface areas. Ratio of radii 3:4. Find ratio of volumes.", "options": {"A": "3:4", "B": "4:3", "C": "9:16", "D": "27:64"}, "correct_answer": "A"},
    {"id": 100, "difficulty": "hard", "question": "Cylinder of height 30 cm cut into two equal cylinders. Total surface area increases by 25%. Find original radius.", "options": {"A": "5 cm", "B": "10 cm", "C": "15 cm", "D": "20 cm"}, "correct_answer": "B"}
  ]
}