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

A borrows a sum of Rs 1000 from his friend B on 31 December 2015 on the condition that he will return the same after one year with the simple interest 12\%. However, A gets into a position of returning the money on 1 May 2016. How much amount he has to return to B?
  1. $1331.5$
  2. $1045$
  3. $1120$
  4. $1040$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Principal = Rs 1000, Rate = 12% per annum. Time period from Dec 31, 2015 to May 1, 2016 = 4 months 1 day = 121 days. Simple Interest = P × R × T / 365 = 1000 × 12 × 121 / (100 × 365) = 145200 / 36500 = Rs 39.78 ≈ Rs 40. Total amount = 1000 + 40 = Rs 1040.

Multiple choice

A fixed amount becomes Rs 4032 in 2 years and Rs 4656 in 3.5 years. Find the simple interest rate.

  1. 10%

  2. 12.5%

  3. 13%

  4. 15%

  5. 22.5%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The difference between amounts after 2 years and 3.5 years is Rs. 4656 - Rs. 4032 = Rs. 624, which is interest for 1.5 years. For simple interest, interest for 2 years would be (624/1.5) × 2 = Rs. 832. So principal = Rs. 4032 - Rs. 832 = Rs. 3200. Rate = (SI × 100) / (P × T) = (832 × 100) / (3200 × 2) = 13%.

Multiple choice

An amount of x is invested at the rate of 10% at simple interest for 3 years and the amount received is further invested in another scheme for 2 years at a compound annual interest rate of 20%. If the last receipt is Rs. 12168, find the value of x.

  1. 4500

  2. 6500

  3. 2500

  4. 5500

  5. 3500
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

First 3 years at 10% SI: Amount = x(1 + 0.10×3) = 1.3x. This amount invested for 2 years at 20% CI: Final = 1.3x × (1.2)² = 1.3x × 1.44 = 1.872x. Given 1.872x = 12168, so x = 12168/1.872 = 6500. Option B is correct. Verification: Year 1-3 SI: 6500 + 1950 = 8450. Year 4-5 CI: 8450 × 1.2 = 10140 (year 4), 10140 × 1.2 = 12168 (year 5). ✓

Multiple choice

A man borrows Rs. 4000 at 8% compound interest for 3 years. At the end of each year he paid Rs. 500. How much amount should he pay at the end of 3rd year to clear the dept?

  1. Rs. 4254.5

  2. Rs. 3465.5

  3. Rs. 3485.2

  4. Rs. 4345.4

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

Calculate compound interest iteratively: Year 1: Rs. 4000 × 1.08 = Rs. 4320, after Rs. 500 payment = Rs. 3820. Year 2: Rs. 3820 × 1.08 = Rs. 4125.60, after payment = Rs. 3625.60. Year 3: Rs. 3625.60 × 1.08 = Rs. 3915.65 final payment. This doesn't match options A-D, so E is correct.

Multiple choice

Any principal become triple in 6 years with compound interest, find the time in which 12000 principal become 29,16,000 amount with compound interest ? चक्रवृद्धि ब्याज के साथ 6 वर्षों में कोई मूलधन 3 गुणा हो जाता है, उस समय का पता लगाएं जिसमें 12,000 मूलधन चक्रवृद्धि ब्याज के साथ 29,16,000 राशि हो जाती है ?

  1. 25

  2. 32

  3. 45

  4. 55

  5. 30
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Amount triples in 6 years: 3 = (1+r)^6. So (1+r) = 3^(1/6). Required: 12000(1+r)^t = 2916000. 2916000/12000 = 243 = 3^5. So (1+r)^t = 3^5. Since (1+r)^6 = 3, we need t such that (1+r)^t = (1+r)^30. Thus t = 30 years.

Multiple choice

Find the CI of 3 years on a sum of 125000 Rs. invested at an interest rate of 18%. 125000 रूपये के मूलधन पर 18% वार्षिक ब्याज की दर से 3 वर्षों का चक्रवृद्धि ब्याज ज्ञात कीजिए।

  1. 82480

  2. 74789

  3. 80379

  4. 72548

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

For compound interest: A = P(1 + r/100)^n. Here: A = 125000(1 + 18/100)³ = 125000(1.18)³ = 125000 × 1.643032 = 205379. CI = A - P = 205379 - 125000 = 80379. Option C (80379) is correct.

Multiple choice

Seema invested on amount of Rs. 16000 for 2 years on compound interest and received on amount of Rs. 17640 on maturity. What is the rate for interest? सीमा ने 16000 रू. की राशि दो वर्षों के लिए चक्रवृद्धि ब्याज पर निवेशित किया और परिपक्वता पर 17640 रू. की राशि प्राप्त की। ब्याज की दर क्या है?

  1. 5%

  2. 8%

  3. 4%

  4. 10%

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

Using A = P(1 + r/100)^n: 17640 = 16000(1 + r/100)². So (1 + r/100)² = 17640/16000 = 1.1025. Taking square root: 1 + r/100 = 1.05, so r/100 = 0.05, giving r = 5%.

Multiple choice

A certain sum amounts to Rs. 29282 in 4 years at 10% per annum, when the interest is compounded annually. What is the simple interest on the same sum for the same time at the same rate?

  1. Rs. 8,500

  2. Rs. 8,000

  3. Rs. 7,600

  4. Rs. 8,400
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Compound interest formula: A = P(1 + r/100)^t. 29282 = P(1.1)^4 = P × 1.4641. Principal P = 29282/1.4641 ≈ 20000. Simple interest = P × r × t/100 = 20000 × 10 × 4/100 = 8000. Option B is correct.

Multiple choice

At what rate of compound interest per annum will a sum of Rs. 1200 become Rs.1348.32 in 2 years? किस दर से 1200 रू. चक्रवृद्धि ब्याज की दर से 2 वर्षो में 1348.32 रू. हो जाएगा ?

  1. 6%

  2. 6.5%

  3. 7%

  4. 7.5%

  5. 8%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using compound interest formula: A = P(1 + r/100)^n. Here A = 1348.32, P = 1200, n = 2. So 1200(1 + r/100)^2 = 1348.32. Dividing: (1 + r/100)^2 = 1348.32/1200 = 1.1236. Taking square root: 1 + r/100 = √1.1236 = 1.06. Therefore r = 6%.

Multiple choice

The compound interest on a certain sum at the rate of 5 p.c.p.a after 3 years is Rs. 1324.05. What is simple interest? एक निश्चित राशि पर 3 वर्षों में 5 प्र.श.प्र.व. की दर से चक्रवृद्धि 1324.05 है। साधारण ब्याज क्या है?

  1. Rs. 1260 1260 रू.

  2. Rs. 1560 1560 रू.

  3. Rs. 1160 1160 रू.

  4. Rs. 1360 1360 रू.

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

CI = P(1 + 5/100)³ - P = P(1.157625 - 1) = 0.157625P = 1324.05, so P = 8400. SI = 8400 × 5 × 3/100 = 1260. The key is finding P from CI first.

Multiple choice

A person invested P on compound interest at the rate of 10% for 2 years, and invested (P+200) at the rate of 14% simple interest for 4 years. The total interest obtained is 6965. Find the total amount (in rupees) invested by the person. एक व्यक्ति ने 2 वर्ष के लिए 10% की दर से चक्रवृद्धि ब्याज पर P रुपये का निवेश किया, और 4 वर्ष के लिए 14% साधारण ब्याज की दर से (P + 200) रुपये का निवेश किया। तथा प्राप्त कुल ब्याज 6965 रुपये है। तो व्यक्ति द्वारा निवेश की गई कुल राशि (रुपये में) ज्ञात करें।

  1. 8900

  2. 18000

  3. 17500

  4. 17800

  5. 15800
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CI at 10% for 2 years: P × 1.21 = 1.21P, so interest = 0.21P. SI at 14% for 4 years: (P + 200) × 0.14 × 4 = 0.56P + 112. Total interest = 0.21P + 0.56P + 112 = 0.77P + 112 = 6965. Solving: 0.77P = 6853, so P = 8900. Total invested = P + (P + 200) = 2P + 200 = 18000.

Multiple choice

A principal of Rs.10,500 at certain rate of simple interest, becomes Rs. 13,825 in 3 4 5 years, then find the simple interest on the same principal in 5 years at twice the rate of interest?

  1. Rs 8,670

  2. Rs 8,470

  3. Rs 8,560

  4. Rs 8,750
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Principal = Rs. 10,500. Amount after 3 4/5 years = Rs. 13,825. Interest earned = 13,825 - 10,500 = Rs. 3,325. Time = 19/5 years. Simple Interest = P × R × T/100 = 10500 × R × (19/5)/100 = 3325. This gives R = 3325 × 5 × 100/(10500 × 19) = 25/3%. New rate = 2R = 50/3%. New interest for 5 years = 10500 × (50/3) × 5/100 = Rs. 8,750.