## Compound Interest – Aptitude Questions and Answers

**Compound Interest aptitude questions and answers section with explanation. Practice online test for various interview, competitive and entrance exams.****1. Compound interest earned on a sum for the second and the third years are Rs.1200 and Rs.1440 respectively. Find the rate of interest?**

A.18% p.a. B.22% p.a. C.20% p.a. D.24% p.a. E.None of these.__Answer:__ C**Explanation:**

Rs.1440 – 1200 = Rs.240 is the interest on Rs.1200 for one year.

Rate of interest = (100 * 240) / (100 * 1) = 20% p.a**2. A sum of Rs.4800 is invested at a compound interest for three years, the rate of interest being 10% p.a., 20% p.a. and 25% p.a. for the 1st, 2nd and the 3rd years respectively. Find the interest received at the end of the three years.**

A.Rs.2520 B.Rs.3120 C.Rs.3320 D.Rs.2760 E.None of these__Answer:__ B**Explanation:**

Let A be the amount received at the end of the three years.

A = 4800[1 + 10/100][1 + 20/100][1 + 25/100]

A = (4800 * 11 * 6 * 5)/(10 * 5 * 4)

A = Rs.7920

So the interest = 7920 – 4800 = Rs.3120**3. The compound and the simple interests on a certain sum at the same rate of interest for two years are Rs.11730 and Rs.10200 respectively. Find the sum.**

A.Rs.18000 B.Rs.17000 C.Rs.18500 D.Rs.17500 E.None of these.__Answer:__ B**Explanation:**

The simple interest for the first year is 10200/2 is Rs.5100 and compound interest for first year also is Rs.5100. The compound interest for second year on Rs.5100 for one year

So rate of the interest = (100 * 1530)/ (5100 * 1) = 30% p.a.

So P = (100 * 10200)/ (30 * 2) = Rs.17000**4. Ravi invested certain amount for two rates of simple interests at 6% p.a. and 7% p.a. What is the ratio of Ravi’s investments if the interests from those investments are equal?**

A.4 : 3 B.3 : 2 C.6 : 5 D.7 : 6 E.None of these__Answer:__ D**Explanation:**

Let x be the investment of Ravi in 6% and y be in 7%

x(6)(n)/100 = y(7)(n)/100

=> x/y = 7/6

x : y = 7 : 6**5. Every year an amount increases by 1/8th of itself. How much will it be after two years if its present value is Rs.64000?**

A.Rs.81000 B.Rs.80000 C.Rs.75000 D.Rs.64000__Answer:__ A**Explanation:**

64000* 9/8 * 9/8 = 81000**6. In one year, the population, of a village increased by 10% and in the next year, it decreased by 10%. If at the end of 2nd year, the population was 7920, what was it in the beginning?**

A.8500 B.8000 C.8100 D.8400__Answer:__ B**Explanation:**

x*110/100 * 90/100 = 7920

X*0.99=7920

X=7920/0.99

=> 8000**7. The population of a city increases at the rate of 4% p.a. but there is an additional annual increase of 1% in the population due to some job seekers. The percentage increase in the population after 2 years is?**

A.10 B.11 C.10.25 D.10.15__Answer:__ C**Explanation:**

100

5 —- I

5

0.25 — II

———–

10.25%**8. Find the amount on Rs.5000 in 2 years, the rate of interest being 4% per first year and 5% for the second year?**

A.Rs.460 B.Rs.5640 C.Rs.5460 D.Rs.5604__Answer:__ C**Explanation:**

5000 * 104/100 * 105/100 => 5460**9. What sum of money put at C.I amounts in 2 years to Rs.8820 and in 3 years to Rs.9261?**

A.Rs.8000 B.Rs.8400 C.Rs.7500 D.None__Answer:__ A**Explanation:**

8820 —- 441

100 —- ? => 5%

x *105/100 * 105/100 = 8820

x*1.1025=8820

x=8820/1.1025 => 8000**10. A sum of money deposited at C.I. amounts to Rs.2420 in 2 years and to Rs.2662 in 3 years. Find the rate percent?**

A.15% B.10% C.7 1/2 % D.8%__Answer:__ B**Explanation:**

2420 — 242

100 — ? => 10%

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