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

The simple interest of a certain sum of money is 240% of principle in 16 years at the certain rate .find the rate of interesrt. किसी मूलधन पर साधारण ब्याज 16 वर्षों में निश्चित व्याज दर पर मूलधन का 240% है |ब्याज दर ज्ञात कीजिए |

  1. 10%

  2. 12%

  3. 15%

  4. 20%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple interest = (P×R×T)/100. Given SI = 240% of P = 12P/5. So 12P/5 = (P×R×16)/100. Solving: 12/5 = 16R/100, which gives 12/5 = 4R/25, so R = (12×25)/(5×4) = 15%.

Multiple choice

Rahul gave 1500 Rs to Arun for 5 years. Arun return him the money with a simple interest at a rate of 14% per annum. Rahul invested this amount with his saving in a bank for 2 years which gives him 20% rate of interest per annum at compound interest. If after 2 years he receive an interest of Rs. 1408. Find the savings which Rahul add in the amount?

  1. 650

  2. 625

  3. 675

  4. 700

  5. 600
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Step 1: Calculate amount from Arun using SI formula: SI = (P × R × T) / 100 = (1500 × 14 × 5) / 100 = Rs. 1050. Total received = Rs. 1500 + 1050 = Rs. 2550. Step 2: Let savings added be x. Total invested = Rs. (2550 + x) at 20% CI for 2 years. Using CI formula: Amount = Principal × (1 + r/100)^t. Interest earned = Rs. 1408. Solving: (2550 + x) × (1.20)^2 - (2550 + x) = 1408. This gives (2550 + x) × 0.44 = 1408, so 2550 + x = 1408 / 0.44 = 3200. Therefore x = 3200 - 2550 = Rs. 625.

Multiple choice

Deepak has Rs.12615 a part of which he gave to Puneet for 6 years and remaining to Shashank for 8 years, at 5% rate of interest compounded annually. If both Puneet and Shashank gave him same amount at the end of their duration. Find the share of Shashank and Puneet respectively.

  1. 6615,6000

  2. 6200,6415

  3. 6400,6215

  4. 6415,6200

  5. 6000,6615
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Let Puneet's share = P and Shashank's share = S. Given: P + S = 12615. Using CI formula A = P(1 + 5/100)^6 = P(1.05)^6 for Puneet and A = S(1.05)^8 for Shashank. Both receive same amount: P(1.05)^6 = S(1.05)^8. This gives P = S(1.05)^2 = S × 1.1025. Substituting: 1.1025S + S = 12615, so 2.1025S = 12615. Solving: S = 12615 / 2.1025 = 6000. Therefore P = 12615 - 6000 = 6615. Share of Shashank and Puneet = 6000, 6615.

Multiple choice

A man borrowed Rs. 15000 at the rate of 12% and another amount at the of 15% for two years. The total interest paid by him was Rs. 9000. How much did he borrow? एक आदमी ने 15000रू. 12% वार्षिक और एक अन्य धनराशि 15% वार्षिक, की दर से दो वर्ष के लिए साधारण ब्याज पर उधार ली। उसने ब्याज कुल 9000 रू. अदा किये उसने कितना उधार लिया?

  1. Rs.27000

  2. Rs.18000

  3. Rs.9000

  4. Rs.36000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interest on Rs.15000 at 12% for 2 years = 15000 × 0.12 × 2 = 3600. Total interest = 9000, so interest on second loan = 9000 - 3600 = 5400. At 15% for 2 years: 5400 = P × 0.15 × 2, so P = 5400 / 0.3 = 18000, matching option B.

Multiple choice

The compound interest on Rs. 12000 for 9 months at 20% per annum, interest being compounded quarterly, is- 12000 रू. पर 20% प्रति वर्ष की दर से त्रैमासिक संयोजित होने वाला 9 महीनों का चक्रवृद्धि ब्याज होगा-

  1. Rs. 1891.50

  2. Rs. 1901.50

  3. Rs. 1791.50

  4. Rs. 1918.50
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For quarterly compounding, rate per quarter = 20%/4 = 5% and time = 9 months = 3 quarters. Amount = 12000 × (1 + 5/100)³ = 12000 × 1.157625 = Rs. 13891.50. Compound Interest = Amount - Principal = 13891.50 - 12000 = Rs. 1891.50. Option B (Rs. 1901.50) is incorrect as it doesn't follow the formula.

Multiple choice

A sum of money was invested at a certain rate of simple interest for 2 years. Had it been invested at 1% higher rate, it would have fetched Rs.24 more interest. The sum of money is साधारण ब्याज की किसी दर से कोई धनराशि 2 वर्ष के लिए निवेशित की गयी । यदि इसे 1% अधिक दर पर निवेशित किया गया होता तो 24 रू. अधिक ब्याज मिलता । वह धनराशि हैः

  1. Rs./रू.1200

  2. Rs./रू.2400

  3. Rs./रू.1500

  4. Rs./रू.1800
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For 2 years, a 1% higher rate yields Rs.24 more interest annually, so Rs.12 extra per year. This means Rs.12 equals 1% of the principal, giving principal as 12 times 100 equals Rs.1200. Formula: extra interest per year equals principal multiplied by rate difference.

Multiple choice

The difference between the compound interest and simple interest on some amount of money for 2 years at 9% per annum is Rs.129.60. The sum of money is - किसी धनराशि पर 9% वार्षिक दर से 2 वर्ष के चक्रवृद्धि तथा साधारण ब्याजों का अंतर 129.60 रू. है, वह धनराशि है -

  1. 16000

  2. 15000

  3. 16500

  4. 15500
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The difference between compound and simple interest for 2 years at rate r percent is given by the formula P times (r over 100) squared. Substituting 129.60 equals P times (9 over 100) squared gives P equals 129.60 times 10000 over 81 equals 16000. This works because compound interest earns interest on interest while simple interest does not.

Multiple choice

On a certain sum of money lent out at 18% p.a. the difference between the compound interest for 1 year payable half yearly, and the simple interest for 1 year is Rs. 162. The sum is - किसी धनराशि पर 18% वार्षिक दर पर प्रत्येक छमाही देय भुगतान के आधार पर प्राप्त एक वर्ष के चक्रवृद्धि ब्याज और एक वर्ष के साधारण ब्याज का अन्तर 162 रू. है। तदनुसार वह राशि कितनी है?

  1. Rs. 81,000

  2. Rs.16,200

  3. Rs. 18,000

  4. Rs. 20,000
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Rate = 18% p.a., half-yearly compounding. For 1 year, effective rate for CI = (1 + 0.18/2)² - 1 = (1.09)² - 1 = 0.1881 or 18.81%. SI for 1 year = 18%. Difference = (18.81 - 18)% of P = 0.81% of P = 162. So P = 162 / 0.0081 = 20000.

Multiple choice

A sum of money becomes 1.331 times in 3 years as compound interest. The rate of interest is - एक राशि 3 वर्षों में चक्रवृद्धि ब्याज से स्वयं का 1.331 गुना हो जाती है | ब्याज की दर है -

  1. 8%

  2. 7.5%

  3. 10%

  4. 50%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Amount becomes 1.331 times in 3 years at compound interest. Since 1.331^(1/3)=1.1, the rate is 10% per annum. Verify: 1×1.1³=1.331, which matches.

Multiple choice

A person deposited Rs.500 for 4 years and Rs.600 for 3 years at the same rate of simple interest in a bank. Altogether he received Rs.190 as interest. The rate of simple interest per annum was- एक व्यक्ति रू.500, 4 वर्षों के लिए और रू.600, 3 वर्षों के लिए एक बैंक में समान साधारण ब्याज की दर से जमा करता है | कुल मिलाकर वह रू.190 ब्याज के रूप में प्राप्त करता है | प्रति वर्ष साधारण ब्याज की दर थी-

  1. 2%

  2. 3%

  3. 4%

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

Total interest=500×4×r/100 + 600×3×r/100 = 190. Simplifying: 2000r/100 + 1800r/100 = 190 gives 38r = 190, so r=5%.

Multiple choice

The difference between the simple interest and the compound interest on a certain sum of money for 3 years at 10% per annum is Rs.15 and 50 paise. The sum is किसी धनराशि पर 10% प्रति वर्ष की ब्याज दर से 3 वर्षों में साधारण ब्याज और चक्रवृद्धि ब्याज का अन्तर 15 रू. 50 पैसे है, तो धनराशि क्या है?

  1. Rs/रू.5000

  2. Rs/रू.550

  3. Rs./रू.500

  4. Rs./रू.1500
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Difference between CI and SI for 3 years at rate r% is P × (r/100)² × (3 + r/100). Given r=10%, difference=15.50. Substituting: 15.50 = P × (1/10)² × (3.10) = P × 0.031. Solving: P = 15.50/0.031 = 500.

Multiple choice

If the simple interest on a certain sum of money is (2700) in (3) years at the rate of interest (12\%) per annum. Find the compound interest of (2) years at the same rate of interest on the same sum?

  1. 2296

  2. 2189

  3. 1908

  4. 1906

  5. 1800
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple Interest formula: SI = P × R × T / 100. 2700 = P × 12 × 3 / 100, so P = 2700 × 100 / 36 = Rs. 7500. Compound Interest for 2 years at 12%: Amount = 7500 × (1 + 12/100)² = 7500 × 1.2544 = 9408. CI = 9408 - 7500 = Rs. 1908. Option A (2296) and B (2189) are calculation errors.

Multiple choice

What will be the difference between the simple interest and compound interest earned on a sum of Rs 985 @ 14 p.c.p.a at the end of two years ? एक 985 रू. की धनराशि का 14 प्रतिशत प्रति वर्ष की दर से दो वर्ष के अन्त में साधारण ब्याज और चक्रवृद्धि ब्याज का अन्तर क्या होगा?

  1. 16.408

  2. 19.306

  3. 14.218

  4. 17.405
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Simple Interest = Prt/100 = 985 × 14 × 2/100 = Rs 275.80. Compound Interest = P[(1+r/100)² - 1] = 985[(1.14)² - 1] = 985[1.2996 - 1] = 985 × 0.2996 = Rs 295.106. The difference is 295.106 - 275.80 = 19.306. The difference between CI and SI for 2 years can also be calculated directly as P(r/100)² = 985(0.14)² = 985 × 0.0196 = 19.306.