{
  "title": "Properties and Operations (Compound Interest) - Grade 9 ICSE",
  "total_questions": 60,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "Compound interest is calculated on ______ principal each year.", "options": {"A": "same", "B": "increasing", "C": "decreasing", "D": "fixed"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "Formula for compound interest when interest compounded annually: A = P(1 + r/100)^t. Here A is ______.", "options": {"A": "interest", "B": "amount", "C": "principal", "D": "time"}, "correct_answer": "B"},
    {"id": 3, "difficulty": "easy", "question": "If time = 2 years, r = 10%, P = 1000, compound interest = amount minus ______.", "options": {"A": "rate", "B": "principal", "C": "time", "D": "100"}, "correct_answer": "B"},
    {"id": 4, "difficulty": "easy", "question": "Compound interest is ______ than simple interest for same rate and time (t > 1).", "options": {"A": "less", "B": "equal", "C": "greater", "D": "half"}, "correct_answer": "C"},
    {"id": 5, "difficulty": "easy", "question": "When interest is compounded half-yearly, rate per half = ______.", "options": {"A": "r", "B": "r/2", "C": "2r", "D": "r/4"}, "correct_answer": "B"},
    {"id": 6, "difficulty": "easy", "question": "When interest is compounded quarterly, time in quarters = ______ × t.", "options": {"A": "2", "B": "4", "C": "12", "D": "1"}, "correct_answer": "B"},
    {"id": 7, "difficulty": "easy", "question": "If P = 2000, r = 5%, t = 1 year, compound interest = ?", "options": {"A": "100", "B": "105", "C": "2100", "D": "210"}, "correct_answer": "A"},
    {"id": 8, "difficulty": "easy", "question": "Amount = Principal + ______.", "options": {"A": "rate", "B": "time", "C": "interest", "D": "tax"}, "correct_answer": "C"},
    {"id": 9, "difficulty": "easy", "question": "If interest is added to principal each year, it is called ______.", "options": {"A": "simple interest", "B": "compound interest", "C": "principal", "D": "deposit"}, "correct_answer": "B"},
    {"id": 10, "difficulty": "easy", "question": "For same principal, rate, time, compound interest ______ simple interest.", "options": {"A": "equals", "B": "is less than", "C": "is more than", "D": "half of"}, "correct_answer": "C"},
    {"id": 11, "difficulty": "easy", "question": "Compounded annually means interest added ______ per year.", "options": {"A": "once", "B": "twice", "C": "four times", "D": "monthly"}, "correct_answer": "A"},
    {"id": 12, "difficulty": "easy", "question": "The formula P(1 + r/100)^t gives ______.", "options": {"A": "simple interest", "B": "amount", "C": "rate", "D": "time"}, "correct_answer": "B"},
    {"id": 13, "difficulty": "easy", "question": "If time t = 0, amount = ______.", "options": {"A": "zero", "B": "principal", "C": "rate", "D": "undefined"}, "correct_answer": "B"},
    {"id": 14, "difficulty": "easy", "question": "For half-yearly compounding, rate used = r/2, time periods = ______.", "options": {"A": "t", "B": "2t", "C": "t/2", "D": "12t"}, "correct_answer": "B"},
    {"id": 15, "difficulty": "easy", "question": "Compound interest depends on ______.", "options": {"A": "P only", "B": "P, r, t", "C": "r only", "D": "t only"}, "correct_answer": "B"},
    {"id": 16, "difficulty": "easy", "question": "If compounded quarterly, n = 4. Then amount = P(1 + r/(100×n))^(n×t). n = ?", "options": {"A": "1", "B": "2", "C": "4", "D": "12"}, "correct_answer": "C"},
    {"id": 17, "difficulty": "easy", "question": "When compounding frequency increases, total interest ______.", "options": {"A": "decreases", "B": "increases", "C": "same", "D": "zero"}, "correct_answer": "B"},
    {"id": 18, "difficulty": "easy", "question": "For 2 years, simple interest = (P×r×t)/100, compound interest = A - P. Which is bigger for t>1?", "options": {"A": "CI", "B": "SI", "C": "equal", "D": "can’t say"}, "correct_answer": "A"},
    {"id": 19, "difficulty": "easy", "question": "If r = 0%, compound interest = ______.", "options": {"A": "P", "B": "0", "C": "t", "D": "100"}, "correct_answer": "B"},
    {"id": 20, "difficulty": "easy", "question": "P = 5000, r = 8%, t = 1 year, compounded annually. Interest = ?", "options": {"A": "400", "B": "5400", "C": "432", "D": "500"}, "correct_answer": "A"},
    {"id": 21, "difficulty": "medium", "question": "If P = 10,000, r = 10% p.a., t = 2 years, find CI. 💵", "options": {"A": "2100", "B": "2000", "C": "2210", "D": "2200"}, "correct_answer": "A"},
    {"id": 22, "difficulty": "medium", "question": "Interest compounded half-yearly: P=8000, r=10%, t=1 year. Find amount.", "options": {"A": "8820", "B": "8800", "C": "8810", "D": "8840"}, "correct_answer": "A"},
    {"id": 23, "difficulty": "medium", "question": "Difference between CI and SI for 2 years at r% = P × (r/100)^2. True?", "options": {"A": "True", "B": "False", "C": "Sometimes", "D": "Never"}, "correct_answer": "A"},
    {"id": 24, "difficulty": "medium", "question": "If compounded quarterly, time in years t=2, number of periods = ?", "options": {"A": "2", "B": "4", "C": "8", "D": "6"}, "correct_answer": "C"},
    {"id": 25, "difficulty": "medium", "question": "P=6000, r=5%, t=3 years, CI = ?", "options": {"A": "945.75", "B": "900", "C": "945", "D": "1000"}, "correct_answer": "A"},
    {"id": 26, "difficulty": "medium", "question": "Amount for ₹12,000 at 8% p.a. compounded annually for 2 years = ?", "options": {"A": "13996.8", "B": "13920", "C": "14000", "D": "13800"}, "correct_answer": "A"},
    {"id": 27, "difficulty": "medium", "question": "CI for 1st year = SI for 1st year. True?", "options": {"A": "True", "B": "False", "C": "Sometimes", "D": "Depends"}, "correct_answer": "A"},
    {"id": 28, "difficulty": "medium", "question": "If rate doubled and time halved, compound interest ______.", "options": {"A": "doubles", "B": "same", "C": "changes", "D": "halves"}, "correct_answer": "C"},
    {"id": 29, "difficulty": "medium", "question": "For half-yearly compounding, effective annual rate is ______ nominal rate.", "options": {"A": "less than", "B": "equal to", "C": "more than", "D": "half of"}, "correct_answer": "C"},
    {"id": 30, "difficulty": "medium", "question": "If P = 1,00,000, r = 6% p.a., t = 3 years, CI (approx) = ?", "options": {"A": "19101.6", "B": "18000", "C": "20000", "D": "19000"}, "correct_answer": "A"},
    {"id": 31, "difficulty": "medium", "question": "Difference CI − SI for P=5000, r=4%, t=2 years = ?", "options": {"A": "8", "B": "16", "C": "32", "D": "40"}, "correct_answer": "A"},
    {"id": 32, "difficulty": "medium", "question": "If amount = 1331, principal = 1000, time = 3 years, r = ?", "options": {"A": "10%", "B": "11%", "C": "12%", "D": "9%"}, "correct_answer": "A"},
    {"id": 33, "difficulty": "medium", "question": "Compounded monthly: n=12. If r=12% p.a., monthly rate = ?", "options": {"A": "1%", "B": "12%", "C": "0.5%", "D": "2%"}, "correct_answer": "A"},
    {"id": 34, "difficulty": "medium", "question": "CI on ₹8000 at 15% p.a. for 2 years = ?", "options": {"A": "2580", "B": "2500", "C": "2600", "D": "2400"}, "correct_answer": "A"},
    {"id": 35, "difficulty": "medium", "question": "If compounded annually and half-yearly for same P, r, t, which gives more interest?", "options": {"A": "half-yearly", "B": "annually", "C": "same", "D": "quarterly"}, "correct_answer": "A"},
    {"id": 36, "difficulty": "medium", "question": "Find CI on ₹7500 at 4% p.a. for 2 years.", "options": {"A": "612", "B": "600", "C": "624", "D": "636"}, "correct_answer": "A"},
    {"id": 37, "difficulty": "medium", "question": "If principal doubles in 6 years at CI, in next 6 years it becomes ______ times original.", "options": {"A": "4", "B": "3", "C": "2", "D": "6"}, "correct_answer": "A"},
    {"id": 38, "difficulty": "medium", "question": "P = 4000, r = 5% p.a., t = 2 years compounded annually. Find amount.", "options": {"A": "4410", "B": "4400", "C": "4415", "D": "4420"}, "correct_answer": "A"},
    {"id": 39, "difficulty": "medium", "question": "Compound interest for third year on ₹10,000 at 10% p.a. = ?", "options": {"A": "1210", "B": "1100", "C": "1000", "D": "1310"}, "correct_answer": "A"},
    {"id": 40, "difficulty": "medium", "question": "Effective annual rate for 10% p.a. compounded half-yearly = ?", "options": {"A": "10.25%", "B": "10.5%", "C": "10%", "D": "11%"}, "correct_answer": "A"},
    {"id": 41, "difficulty": "hard", "question": "If difference between CI and SI for 3 years at 10% p.a. is ₹310, find principal. 🤔", "options": {"A": "10000", "B": "8000", "C": "12000", "D": "15000"}, "correct_answer": "A"},
    {"id": 42, "difficulty": "hard", "question": "A sum becomes ₹13,310 in 2 years at 10% p.a. compounded annually. Find principal.", "options": {"A": "11000", "B": "10000", "C": "12000", "D": "13000"}, "correct_answer": "A"},
    {"id": 43, "difficulty": "hard", "question": "At what rate% p.a. will ₹6250 become ₹6760 in 2 years, compounded annually?", "options": {"A": "4%", "B": "5%", "C": "6%", "D": "8%"}, "correct_answer": "A"},
    {"id": 44, "difficulty": "hard", "question": "If CI for 2 years at 4% p.a. is ₹408, find principal.", "options": {"A": "5000", "B": "6000", "C": "4000", "D": "8000"}, "correct_answer": "A"},
    {"id": 45, "difficulty": "hard", "question": "Half-yearly compounding: P=16000, r=5% p.a., t=1.5 years. Find amount.", "options": {"A": "17230.25", "B": "17200", "C": "17150", "D": "17300"}, "correct_answer": "A"},
    {"id": 46, "difficulty": "hard", "question": "Difference CI − SI for 3 years at r% = P × (r/100)^2 × (3 + r/100). True?", "options": {"A": "True", "B": "False", "C": "Sometimes", "D": "Cannot say"}, "correct_answer": "A"},
    {"id": 47, "difficulty": "hard", "question": "If amount after 2 years at CI is ₹12100 and rate 10% p.a., principal?", "options": {"A": "10000", "B": "11000", "C": "12000", "D": "12100"}, "correct_answer": "A"},
    {"id": 48, "difficulty": "hard", "question": "A sum doubles in 5 years at CI. In how many years will it become 8 times?", "options": {"A": "15", "B": "20", "C": "10", "D": "12"}, "correct_answer": "A"},
    {"id": 49, "difficulty": "hard", "question": "Find CI on ₹20,000 at 12% p.a. for 9 months compounded quarterly.", "options": {"A": "1854", "B": "1900", "C": "1800", "D": "2000"}, "correct_answer": "A"},
    {"id": 50, "difficulty": "hard", "question": "If compounded annually and half-yearly difference for 2 years at 8% on ₹5000 = ?", "options": {"A": "8.64", "B": "10", "C": "12", "D": "0"}, "correct_answer": "A"},
    {"id": 51, "difficulty": "hard", "question": "CI for third year on ₹8000 at 5% p.a. = ?", "options": {"A": "441", "B": "420", "C": "400", "D": "440"}, "correct_answer": "A"},
    {"id": 52, "difficulty": "hard", "question": "Effective annual rate for 8% p.a. compounded quarterly = ?", "options": {"A": "8.24%", "B": "8%", "C": "8.5%", "D": "8.75%"}, "correct_answer": "A"},
    {"id": 53, "difficulty": "hard", "question": "If CI for 2 years is ₹410 and SI for same is ₹400, find rate%.", "options": {"A": "5%", "B": "10%", "C": "8%", "D": "6%"}, "correct_answer": "A"},
    {"id": 54, "difficulty": "hard", "question": "Principal that amounts to ₹19,965 in 3 years at 10% p.a. compounded annually?", "options": {"A": "15000", "B": "16000", "C": "14000", "D": "17000"}, "correct_answer": "A"},
    {"id": 55, "difficulty": "hard", "question": "Find time if ₹5000 becomes ₹6655 at 10% p.a. compounded annually.", "options": {"A": "3 years", "B": "2 years", "C": "4 years", "D": "5 years"}, "correct_answer": "A"},
    {"id": 56, "difficulty": "hard", "question": "Difference CI − SI for 2 years at r% = Pr²/10000. If P=2500, diff=1, r=?", "options": {"A": "2%", "B": "4%", "C": "5%", "D": "10%"}, "correct_answer": "A"},
    {"id": 57, "difficulty": "hard", "question": "CI on ₹12,000 for 1.5 years at 10% p.a. compounded half-yearly?", "options": {"A": "1891.5", "B": "1900", "C": "1850", "D": "2000"}, "correct_answer": "A"},
    {"id": 58, "difficulty": "hard", "question": "If amount after 2 years is ₹2420 and principal ₹2000, rate% = ?", "options": {"A": "10%", "B": "12%", "C": "15%", "D": "8%"}, "correct_answer": "A"},
    {"id": 59, "difficulty": "hard", "question": "A sum at CI doubles in 6 years. In 18 years, it will be ______ times original.", "options": {"A": "8", "B": "6", "C": "4", "D": "12"}, "correct_answer": "A"},
    {"id": 60, "difficulty": "hard", "question": "Principal = ₹8000, rate = 5% p.a., time 3 years, CI when compounded annually = ?", "options": {"A": "1261", "B": "1200", "C": "1300", "D": "1250"}, "correct_answer": "A"}
  ]
}