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

Mr. Raj invested an amount of Rs. 21250 for 6 years. At what rate of simple interest will he obtain the total amount of Rs. 26350 at the end of 6 years? मि. राज 21250 रू. की धनराशि 6 वर्ष के लिए निवेश करते है। साधारण ब्याज की किस दर पर 6 वर्ष के अन्त में 26350 रू. की कुल धनराशि प्राप्त होगी?

  1. 3%

  2. 4%

  3. 4.5%

  4. 6.2%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interest earned = 26350 - 21250 = 5100 over 6 years. Simple Interest formula: SI = P×R×T/100. 5100 = 21250×R×6/100. R = 5100×100/(21250×6) = 510000/127500 = 4%. Option B is correct. Options A, C, D are incorrect rates.

Multiple choice

If Rs. 5000 amounts to Rs. 5750 in three years, what will Rs. 6000 amounts to in 4 years at the same rate of simple interest? यदि 5000 रूपये धनराशि तीन वर्षों में 5750 रूपये हो जाती है तो 6000 रूपये की धनराशि 4 वर्षों में इसी समान साधारण ब्याज की दर पर क्या होगी?

  1. 6750

  2. 6950

  3. 7150

  4. 7200
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

First find the rate: Interest = 5750 - 5000 = 750 on 5000 for 3 years, so Rate = (750 × 100)/(5000 × 3) = 5% per annum. For Rs. 6000 at 5% for 4 years: Interest = (6000 × 5 × 4)/100 = 1200, so Amount = 6000 + 1200 = 7200.

Multiple choice

The rate of simple interest on an amount of money is 6 percent per annum for the first two years, 9 percent per annum for the next five years and 13 percent per annum for the period beyond seven years. if the total interest on a sum end of ten years is Rs. 7680, what is the sum? एक धनराशि पर साधारण ब्याज की दर 6 प्रतिशत वार्षिक प्रथम दो वर्ष के लिए 9 प्रतिशत वार्षिक अगले 5 वर्षों के लिए और 13 प्रतिशत वार्षिक बाद के सात वर्षों के लिए हैं यदि धनराशि पर दस वर्षों की समाप्ति पर कुल ब्याज 7680 रूपये हो तो धनराशि क्या है?

  1. 8000

  2. 8800

  3. 9600

  4. 12100
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For principal P: Interest for first 2 years at 6% = 0.12P. For next 5 years at 9% = 0.45P. For last 3 years at 13% = 0.39P. Total interest = 0.96P = 7680, so P = 7680/0.96 = 8000. The varying rates apply sequentially to the same principal.

Multiple choice

The compound interest on Rs. 16000 for 9 months at 20% per annum, interest being compounded quarterly, is - 16000 रूपये पर 20% की वार्षिक चक्रवृद्धि ब्याज की दर पर 9 महीने के लिए ब्याज तिमाही संयोजित होने पर, ब्याज है-

  1. 1856

  2. 1660

  3. 2522

  4. 2225
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For quarterly compounding, rate per quarter = 20%/4 = 5%, and time = 9 months = 3 quarters. Amount = 16000 × (1 + 0.05)^3 = 16000 × 1.157625 = 18522. Compound Interest = 18522 - 16000 = 2522. Options A and B are significantly lower.

Multiple choice

A sum of money becomes 21/20 of itself in 1/5 years at a certain rate of simple interest. The rate of Interest per annum is- कोई धन साधारण ब्याज की दर से अपने का 21/20 गुना 1/5 वर्षों में हो जाता है। ब्याज की वार्षिक दर क्या है?

  1. 15%

  2. 25%

  3. 20%

  4. 5%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using SI formula: Amount = P(1 + rt/100). Here Amount = (21/20)P, time = 1/5 year. So (21/20) = 1 + r/500. Solving: 1/20 = r/500, r = 25%.

Multiple choice

A sum of money double itself at a compound interest in 15 years. In how many years will it become 8 times. कोई धन चक्रवृद्धि ब्याज की दर से 15 वर्षों में अपने का दुगना हो जाता है। कितने वर्षों में धन अपने का आठ गुना हो जायेगा।

  1. 30 years / वर्ष

  2. 45 years / वर्ष

  3. 60 years / वर्ष

  4. 40 years / वर्ष
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Money doubles in 15 years, so 2× in 15 years. To reach 8×, note that 8 = 2³, so we need 3 doubling periods: 3 × 15 = 45 years. Alternatively, using compound interest formula: 2⁴⁵/¹⁵ = 2³ = 8.

Multiple choice

Rahul lend money to Puneet, Manish and Sandeep with the rate of interest of 10%, 12% and 15% per annum respectively. If the total interest accrued in 1 year was 3200 and the amount he lend to Sandeep is 150% of the amount he lend to Puneet and 240% of the amount he lend to Manish. What amount he lend to Manish?

  1. 4000

  2. 9000

  3. 8000

  4. 7000

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

Let Puneet = x, Manish = y, Sandeep = z. z = 1.5x = 2.4y. From z = 2.4y, y = z÷2.4. Interest: 0.1x + 0.12y + 0.15z = 3200. Substituting: 0.1x + 0.12(z÷2.4) + 0.15z = 3200. Since z = 1.5x: 0.1x + 0.12(1.5x÷2.4) + 0.15(1.5x) = 3200. 0.1x + 0.075x + 0.225x = 3200. 0.4x = 3200, x = 8000. y = 8000÷1.6 = 5000. But 5000 is not in A-D. Answer E (None of these) is correct.

Multiple choice

Mohit borrowed a sum of Rs. 1150 from Anil at the simple rate of 6 p.c.p.a. for 3 years. He then added some more money to the borrowed sum and lent it to Sunil for the same time at 9 p.c.p.a. at simple interest. If Mohit gains Rs. 274.95 from the whole transaction, then what is the sum lent by him to Sunil?

  1. Rs. 1820

  2. Rs. 1758

  3. Rs. 1785

  4. Rs. 1930

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

Mohit pays 6% of 1150 for 3 years: 1150×0.06×3 = 207. Mohit lends x at 9% for 3 years: 0.09×x×3 = 0.27x. Gain = 0.27x - 207 = 274.95. So 0.27x = 481.95, x = 481.95÷0.27 = 1785. Answer C is correct. The profit is the difference between interest received and interest paid.

Multiple choice

What will be the compound interest accrued on an amount of Rs 9500 at the rate of 10 p.c.p.a. after 2 years?

  1. Rs 1975

  2. Rs 1985

  3. Rs 1965

  4. Rs 1955

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

Compound Interest formula: A = P(1 + r/100)^n. For P = 9500, r = 10%, n = 2: A = 9500(1.1)^2 = 9500 × 1.21 = Rs. 11495. Compound Interest = A - P = 11495 - 9500 = Rs. 1995. This exact amount (Rs. 1995) is NOT in options A-D, so 'None of these' (E) is correct.

Multiple choice

What would be the compound interest obtained on an amount of Rs. 1500 at the rate of 8 percent per annum after 2 years ?

  1. Rs. 251.60

  2. Rs. 249.60

  3. Rs. 248.60

  4. Rs. 252.60

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

Principal = Rs 1500, rate = 8%, time = 2 years. CI = P(1 + r/100)^t - P = 1500(1 + 8/100)^2 - 1500 = 1500(1.08)^2 - 1500 = 1500(1.1664) - 1500 = 1749.60 - 1500 = Rs 249.60. Alternatively: 1st year interest = 1500 × 0.08 = 120, 2nd year interest = (1500 + 120) × 0.08 = 1620 × 0.08 = 129.60. Total CI = 120 + 129.60 = 249.60.

Multiple choice

Kush invested a certain sum of money at a certain rate of interest after 6 year he receive Rs.12000 as simple interest. If Kush double his investment in every 2 years then what will be the interest get at the end of 6 years?(in Rs)

  1. 20000

  2. 24000

  3. 28000

  4. 32000

  5. 16000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let P be the initial principal and r the annual interest rate. From the first statement: SI at 6 years = Pr × 6 = 12000, so Pr = 2000. If investment doubles every 2 years, the principals are: years 0-2: P, years 2-4: 2P, years 4-6: 4P. Total SI = Pr + 2Pr + 4Pr = 7Pr = 7 × 2000 = 28000.

Multiple choice

A sum of Rs. 55000 is divided into two parts and invested at 4% for 3 years and at 5% p.a. for 6 years respectively. If interest earned on the second part is three times of that on the first part, find the amount invested in the second part?

  1. Rs. 40,000

  2. Rs. 15, 000

  3. Rs. 30,000

  4. Rs. 25, 000

  5. Rs. 20, 000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the amounts be x and (55000 - x). SI1 = x × 4 × 3 / 100 = 12x/100. SI2 = (55000 - x) × 5 × 6 / 100 = 30(55000 - x)/100. Given SI2 = 3 × SI1: 30(55000 - x)/100 = 3 × 12x/100 = 36x/100. Therefore: 1650000 - 30x = 36x, so 66x = 1650000, x = 25000. Second part = 55000 - 25000 = 30000. The calculation confirms option C is correct.