IndiaBIX

Aptitude - Compound Interest

Exercise : Compound Interest - General Questions
11.
Simple interest on a certain sum of money for 3 years at 8% per annum is half the compound interest on Rs. 4000 for 2 years at 10% per annum. The sum placed on simple interest is:
Rs. 1550
Rs. 1650
Rs. 1750
Rs. 2000
Answer: Option
Explanation:

C.I.
= Rs. 4000 x 1 + 10 2 - 4000
100
= Rs. 4000 x 11 x 11 - 4000
10 10
= Rs. 840.

Sum = Rs. 420 x 100 = Rs. 1750.
3 x 8

12.
If the simple interest on a sum of money for 2 years at 5% per annum is Rs. 50, what is the compound interest on the same at the same rate and for the same time?
Rs. 51.25
Rs. 52
Rs. 54.25
Rs. 60
Answer: Option
Explanation:

Sum = Rs. 50 x 100 = Rs. 500.
2 x 5

Amount
= Rs. 500 x 1 + 5 2
100
= Rs. 500 x 21 x 21
20 20
= Rs. 551.25

C.I. = Rs. (551.25 - 500) = Rs. 51.25

13.
The difference between simple interest and compound on Rs. 1200 for one year at 10% per annum reckoned half-yearly is:
Rs. 2.50
Rs. 3
Rs. 3.75
Rs. 4
None of these
Answer: Option
Explanation:

S.I. = Rs 1200 x 10 x 1 = Rs. 120.
100

C.I. = Rs. 1200 x 1 + 5 2 - 1200 = Rs. 123.
100

Difference = Rs. (123 - 120) = Rs. 3.

14.
The difference between compound interest and simple interest on an amount of Rs. 15,000 for 2 years is Rs. 96. What is the rate of interest per annum?
8
10
12
Cannot be determined
None of these
Answer: Option
Explanation:

15000 x 1 + R 2 - 15000 - 15000 x R x 2 = 96
100 100

15000 1 + R 2 - 1 - 2R = 96
100 100

15000 (100 + R)2 - 10000 - (200 x R) = 96
10000

R2 = 96 x 2 = 64
3

R = 8.

Rate = 8%.

15.
The compound interest on a certain sum for 2 years at 10% per annum is Rs. 525. The simple interest on the same sum for double the time at half the rate percent per annum is:
Rs. 400
Rs. 500
Rs. 600
Rs. 800
Answer: Option
Explanation:

Let the sum be Rs. P.

Then, P 1 + 10 2 - P = 525
100

P 11 2 - 1 = 525
10

P = 525 x 100 = 2500.
21

Sum = Rs . 2500.

So, S.I. = Rs. 2500 x 5 x 4 = Rs. 500
100

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers