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

If the rate of interest is 10% per annum and is compounded half yearly, the principal of Rs 400 in 3/2 years will amount to - यदि ब्याज की दर 10% वार्षिक है और वह अर्धवार्षिक संयोजित की जाती है, तो मूलधन 400 रू. है 3/2 वर्षो में कितनी राशि हो जायेगा?

  1. Rs 463.00

  2. Rs 463.05

  3. Rs 463.15

  4. Rs 463.20
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Half-yearly compounding means 2 periods per year. For 3/2 years = 1.5 years, we have 3 periods. Rate per period = 10%/2 = 5%. A = 400(1+5/100)^3 = 400(1.05)^3 = 400 × 1.157625 = 463.05. Option B is correct.

Multiple choice

If the interest on a sum of money be 1 paisa per rupee per month, what is the rate percent per annum? यदि किसी धनराशि पर ब्याज 1 पैसा प्रति रूपया प्रति माह हो , तो वार्षिक ब्याज दर क्या प्रतिशत क्या होगा ?

  1. 10 %

  2. 12 %

  3. 15 %

  4. 10.5 %
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

1 paisa per rupee per month means 1 paisa interest on ₹1 (100 paisa) monthly. Monthly rate = 1/100 = 1%. Annual rate = 1% × 12 = 12%. Option A (10%) would result from using 10 months instead of 12 in the calculation.

Multiple choice

Rs. 8000 invested at compound interest gives Rs. 1261 as interest after 3 years. The rate of interest per annum ? रू. 8000 पर तीन वर्षों का ब्याज चक्रवृद्धि ब्याज दर से रू. 1261 है। ब्याज दर ज्ञात कीजिए।

  1. 25%

  2. 17.5%

  3. 10%

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

Using compound interest formula: A = P(1 + r/100)³. Interest = 8000[(1 + r/100)³ - 1] = 1261. Therefore (1 + r/100)³ = 9261/8000 = 3.5³/4³ = (3.5/4)³. Taking cube root: 1 + r/100 = 3.5/4 = 0.875. Thus r/100 = -0.125, giving r = 5%. Option A (25%) would give much higher interest of Rs. 1953. Option B (17.5%) would give Rs. 4629. Option C (10%) would give Rs. 2648.

Multiple choice

What will be compound interest obtained on an amount of Rs.64000 at the rate of 11 p.c.p.a. after 2 years?

  1. Rs.14854.4

  2. Rs.15854.4

  3. Rs.16854.4

  4. Rs.15844.4

  5. Rs.14844.4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Compound Interest formula: A = P(1 + r/100)^n. Here P = 64000, r = 11%, n = 2. Amount after 2 years = 64000 × (1.11)² = 64000 × 1.2321 = 78854.4. Compound Interest = Amount - Principal = 78854.4 - 64000 = 14854.4. Alternatively, year 1: 64000 × 0.11 = 7040, new principal = 71040. Year 2: 71040 × 0.11 = 7814.4. Total CI = 7040 + 7814.4 = 14854.4.

Multiple choice

What will be the compound interest obtained on a principal amount of Rs. 6800 at the rate of 4% per annum in 2 years?

  1. Rs.545.68

  2. Rs. 554.88

  3. Rs. 635.54

  4. Rs. 564.38

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

Use the compound interest formula: A = P(1 + r)^t. Here P = 6800, r = 0.04, t = 2. Amount = 6800 × (1.04)^2 = 6800 × 1.0816 = 7354.88. Compound Interest = Amount - Principal = 7354.88 - 6800 = 554.88. Option B is correct. Option A would be simple interest for 2 years, and other options are calculation errors.

Multiple choice

The SI on a sum of money will be Rs.2500 after 5 years. In the next 5 years Principal is trebled, what will be the total interest at the end of the 10th year?

  1. Rs. 10000

  2. Rs. 11500

  3. Rs. 13420

  4. Rs. 14100

  5. Rs. 15100
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For the first 5 years, SI = Rs. 2500. Let Principal = P and Rate = R%. Then SI = (P × R × 5)/100 = 2500, so P × R = 50000. In the next 5 years, principal becomes 3P. New SI = (3P × R × 5)/100 = 15 × (P × R)/100 = 15 × 50000/100 = Rs. 7500. Total interest after 10 years = 2500 + 7500 = Rs. 10000. The key insight is that SI is directly proportional to principal.

Multiple choice

What will be compound interest earned on an amount of Rs 7500 @ 9 p.c.p.a after 3 years ?

  1. Rs. 2812.7175

  2. Rs. 2612.7175

  3. Rs. 2412.7175

  4. Rs. 2212.7175

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

Use compound interest formula A = P(1 + r/100)^n. Here P = 7500, r = 9%, n = 3. Amount = 7500 × (1.09)^3 = 7500 × 1.295029 = 9,712.7175. Compound Interest = Amount - Principal = 9,712.7175 - 7,500 = 2,212.7175. Remember that compound interest includes interest on previously earned interest, unlike simple interest which is only on the principal.

Multiple choice

The difference between compound and simple interest on an amount of Rs. 15000 after 2 years is Rs 96. What is the rate of interest per annum ?

  1. 8%

  2. 10%

  3. 14%

  4. 15%

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

Use the formula for difference between CI and SI for 2 years: D = P(r/100)². Here D = 96, P = 15000. So 96 = 15000(r/100)². This gives 96 = 15000 × r²/10000, or r² = 96 × 10000/15000 = 64. Therefore r = 8%. To verify: SI = 15000 × 8 × 2/100 = 2400. CI = 15000(1.08)² - 15000 = 17496 - 15000 = 2496. Difference = 2496 - 2400 = 96.

Multiple choice

What sum of money at compound interest will amount to Rs. 26194.40 in three years, if the rate of interest is 5% for the first year, 8% for the second year and 10% for the third years? कितने रूपयें की धनराशि तीन वर्षो में चक्रवृद्धि ब्याज की दर पर 26194.40 रू. हो जायेगी। यदि ब्याज की दर प्रथम वर्ष के लिए 5%, दूसरे वर्ष के लिए 8% और तीसरे वर्ष के लिए 10% है?

  1. Rs. 20000

  2. Rs. 21000

  3. Rs. 22000

  4. Rs. 23000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let P be the principal. After 3 years: P×1.05×1.08×1.10 = 26194.40. So P = 26194.40/(1.05×1.08×1.10) = 26194.40/1.2474 = Rs. 21000. Each year, different rates apply to the accumulated amount.

Multiple choice

What sum of money will amount to Rs. 575 in 3 years and to Rs. 625 in 5 years at simple interest? वह धनराशि ज्ञात करे जो साधारण ब्याज से 3 वर्षों में 575 रू. और 5 वर्ष में 625 रू. हो जाती है ?

  1. Rs. 520

  2. Rs. 480

  3. Rs. 500

  4. Rs. 450
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The difference between amounts after 5 and 3 years (Rs. 50) equals simple interest for 2 years, so annual interest is Rs. 25. In 3 years, total interest is Rs. 75, making principal = 575 - 75 = Rs. 500. Verify: At 5% rate, after 5 years, 500 + 125 = Rs. 625.

Multiple choice

Anurag invests Rs. 9525 in a bond which gives interest at 3% per annum during the first year, 5% during the second year and 8% during the third year. How much amount does he get at the end of the third year. अनुराग 9525 रू. ऐसे बांड में निवेश करता है जो पहले वर्ष 3% प्रतिवर्ष की दर से, दूसरे वर्ष 5% प्रतिवर्ष की दर से और तीसरे वर्ष 8% प्रतिवर्ष की दर से ब्याज देते हैं। तीसरे वर्ष के अंत में उसे कितनी धनराशि मिलेगी?

  1. Rs. 11125.40

  2. Rs. 11050.60

  3. Rs. 12060.50

  4. Rs. 13025.40
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Apply compound interest sequentially: After year 1 at 3%: 9525 × 1.03 = 9810.75. After year 2 at 5%: 9810.75 × 1.05 = 10301.29. After year 3 at 8%: 10301.29 × 1.08 = 11125.40. Each year's interest is calculated on the accumulated amount.

Multiple choice

At what rate percent of compund interest, does a sum of money becomes four fold in 4 years? (Approx). चक्रवृद्धि ब्याज के कितने प्रतिशत वार्षिक ब्याज की दर से कोई धनराशि 4 वर्ष में चौगुनी हो जाती है? (लगभग)

  1. 44%

  2. 41%

  3. 39%

  4. 73%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For sum to become 4 times in 4 years at compound interest: P(1+r)⁴ = 4P, so (1+r)⁴ = 4. Taking fourth root: 1+r = 4^(1/4) ≈ 1.414, so r ≈ 41.4%. Check: (1.41)⁴ = 1.41² × 1.41² = 1.99 × 1.99 ≈ 3.96 ≈ 4.