Quantitative Aptitude

Simple and Compound Interest

3,394 Questions
All Simple interest and its inverse forms 768 Compound interest with annual compounding 742 Simple-interest growth and split sums 626 Difference between compound and simple interest 479 Half-yearly and quarterly compounding 252 Changing rates and fractional years 201 Installments (CI based) 190 Ratio of principal to interest 118 Population growth and depreciation 16

Simple and Compound Interest Questions

Multiple choice

Shantanu borrowed Rs. 2.5 lakh from a bank to purchase one car. If the rate of interest be 6% per annum compounded annually, what payment he will have to make after 2 years 6 months?

  1. Rs. 189315

  2. Rs. 389335

  3. Rs. 489425

  4. Rs. 289325

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amount after 2 years = 250000 × (1.06)² = 250000 × 1.1236 = Rs. 280900. For next 6 months, apply simple interest: 280900 × 6/100 × 0.5 = Rs. 8427. Total = 280900 + 8427 = Rs. 289327. Option D matches.

Multiple choice

A sum of money was invested for “X” years in scheme A offering simple interest. The amount received after “X” years was twice the sum of money invested in the scheme. What will be the amount received for scheme A, when a sum of Rs 2800, is invested for “2X” years. स्कीम A में "X" वर्षों के लिए एक धन लगाया गया जो साधारण ब्याज प्रदान करता है। “X” वर्षों के बाद प्राप्त राशि योजना में निवेश की गयी राशि की दोगुना थी। योजना A से प्राप्त राशि क्या होगी, जब 2800 रुपये की राशि "2X" वर्षों के लिए निवेश की जाती है।

  1. 11200

  2. 5600

  3. 8400

  4. 9600

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let principal = P. After X years at simple interest, amount = 2P, so SI = P. This means r = 100/X%. For new investment: P = 2800, time = 2X years. SI = 2800 × (100/X) × 2X / 100 = 5600. Amount = 2800 + 5600 = 8400. Option C is correct.

Multiple choice

If the compound interest accrued on an amount of rs.12000 in two years is Rs. 1738.80 at the certain rate of interest .find the rate of interest. 12000 रु. की धनराशि पर किसी निश्चित ब्याज दर से 2 वर्ष में चक्रवृधि ब्याज 1738.80 रु. हो तो ब्याज दर ज्ञात कीजिए |

  1. 5%

  2. 7%

  3. 6%

  4. 7.5%

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using compound interest formula: CI = P[(1 + r/100)^2 - 1] = 1738.80. So 12000[(1 + r/100)^2 - 1] = 1738.80. Therefore (1 + r/100)^2 - 1 = 1738.80/12000 = 0.1449. Then (1 + r/100)^2 = 1.1449, giving 1 + r/100 = 1.07, so r = 7%. Option B is correct.

Multiple choice

A sum of money amounts to Rs.12322.8 after 7 years and Rs.15724.8 after 12 years at the same rate of simple interest. What is the rate of interest per annum? एक धनराशि साधारण ब्याज की दर से 7 वर्षों में 12322.8 रु. हो जाती है और समान ब्याज दर से 12 वर्षों में यह 15724.8 रु. हो जाती है | प्रति वर्ष ब्याज की दर क्या है ?

  1. 5%

  2. 7%

  3. 8%

  4. 10%

  5. 9%
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Interest for 5 years (12-7) = 15724.8 - 12322.8 = Rs. 3402. Simple Interest per year = 3402/5 = Rs. 680.40. Total amount after 7 years = Principal + (7 × 680.40). 12322.8 = P + 4762.80. Principal P = 12322.8 - 4762.80 = Rs. 7560. Rate = (680.40/7560) × 100 = 9%. Verification: P = 7560, after 12 years: 7560 + (12 × 680.40) = 7560 + 8164.80 = 15724.80. ✓

Multiple choice

Find the difference between compound interest and simple interest on a sum of Rs.48000 at the rate of 15% per annum for three years ? तीन साल के लिए प्रति वर्ष 15% की दर से 48000 रुपये की राशि पर चक्रवृद्धि ब्याज और साधारण ब्याज के बीच अंतर ज्ञात कीजिये ?

  1. Rs. 3200

  2. Rs. 3204

  3. Rs. 3402

  4. Rs. 3202

  5. None of these इनमे से कोई नही
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple Interest for 3 years at 15% on Rs. 48000: SI = P × R × T / 100 = 48000 × 15 × 3 / 100 = Rs. 21600. Compound Interest for 3 years at 15% on Rs. 48000: CI = P(1 + R/100)^T - P = 48000(1.15)³ - 48000 = 48000(1.520875) - 48000 = 73002 - 48000 = Rs. 25002 (approx). Difference = CI - SI = 25002 - 21600 = Rs. 3402. Alternatively, use the direct formula: Difference = P(R/100)²(3 + R/100) = 48000(0.15)²(3.15) = 48000 × 0.0225 × 3.15 = Rs. 3402.

Multiple choice

A certain sum of money becomes Rs. 6600 after 2 years at certain rate of simple interest, and it becomes Rs. 7200 after 4 years. Then find the C.I. on the same sum of money at 10% p.a. after 2 years compounded annually?

  1. Rs. 840

  2. Rs. 1260

  3. Rs. 630

  4. Rs. 1680

  5. Rs. 1540
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interest for 2 years = 7200-6600 = 600. Simple interest per year = 300. Principal = 6600-600 = 6000. CI at 10% for 2 years: 6000(1.1²-1) = 6000 × 0.21 = 1260.

Multiple choice

Simple interest on a certain sum for 2 years is 800 and compound interest for the same sum for the same time is 840, then find the annual rate of interest?

  1. 10%

  2. 20%

  3. 15%

  4. 25%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let rate = r%. SI for 2 years = 2r% of P = 800. CI for 2 years = P[(1 + r/100)² - 1] = P[2r/100 + r²/10000] = 800 + Pr²/10000 = 840. Difference = 40 = Pr²/10000. From SI: P = 80000/2r = 40000/r. Substituting: (40000/r) × r²/10000 = 40, giving r = 10%. Verify: SI = 400, CI = 440, difference = 40 ✓

Multiple choice

Rahul invest Rs. x at simple interest for 4 years and after 4 years he received the total amount of Rs.2x. Suresh invest Rs. x at simple interest for 2 years and Sam invest Rs. x at compound interest for 2 years. All the three persons are investing the same rate of interest. If the total interest received by both Sam and Suresh together is Rs.832 more than the interest received by Rahul? then find the value of x?

  1. 13312

  2. 12890

  3. 13229

  4. 12762

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For Rahul (SI for 4 years to get 2x): Interest = x, so rate r = (x × 100)/(x × 4) = 25%. For Suresh (SI for 2 years): Interest = (x × 25 × 2)/100 = 0.5x. For Sam (CI for 2 years): Interest = x(1.25² - 1)x = 0.5625x. Given: 0.5x + 0.5625x - x = 832, so 0.0625x = 832, giving x = 13312.

Multiple choice

A sum of money amounts to Rs. 1500 after 3 years and Rs. 2000 after 5 years at the same rate of SI. What is the rate of interest per annum?

  1. 33.33%

  2. 45%

  3. 60%

  4. 30%

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let principal be P. After 3 years at simple interest: Amount = P + SI = P + (P × R × 3)/100 = Rs 1500. After 5 years: Amount = P + (P × R × 5)/100 = Rs 2000. The difference between 5-year and 3-year amounts represents interest for 2 years: (P × R × 5)/100 - (P × R × 3)/100 = 2000 - 1500, giving (P × R × 2)/100 = 500, so (P × R)/100 = 250. From the 3-year equation: P + 3 × 250 = 1500, so P = 750. Using (P × R)/100 = 250: (750 × R)/100 = 250, giving R = 25000/750 = 33.33%.

Multiple choice

A sum was invested, on simple interest at a certain rate for 2 years. Had it been put at 3% higher rate, it would have fetched Rs.144 more. The sum is एक राशि को साधारण ब्याज की किसी दर पर 2 वर्ष के लिए निवेश किया गया। यदि उसका निवेश 3% अधिक दर पर किया गया होता तो 144 रू. अधिक मिलते। राशि है

  1. Rs.2400

  2. Rs.2600

  3. Rs.2000

  4. Rs.3000
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Additional interest at 3% higher rate for 2 years = P × 3/100 × 2 = 144. So P × 0.06 = 144, giving P = 144/0.06 = Rs. 2400. Verification: At original rate r, interest = 2400 × r × 2. At (r+3)%, interest = 2400 × (r+3) × 2. Difference = 2400 × 3 × 2 = 14400 × 0.01 = Rs. 144. Option A is correct.

Multiple choice

Raj borrowed a certain sum of money from Rahul at the rate of 5% per annum simple interest for the first four years and at the rate of 7.5% per annum for the next six years and at the rate of 9% per annum for the period beyond ten years. If he pays a total of Rs. 12100 as interest only at the end of 15 years, how much money did he borrow?

  1. Rs. 12000

  2. Rs. 18000

  3. Rs. 9000

  4. Rs. 15000

  5. None of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Interest for first 4 years at 5% = 20% of P. Next 6 years at 7.5% = 45% of P. Remaining 5 years at 9% = 45% of P. Total interest = (20 + 45 + 45)% of P = 110% of P = 12100. Principal P = 12100/1.1 = Rs. 11000. Option E (None of these) is correct since 11000 is not listed in A-D.