# Quantitative Aptitude: Simple/Compound Interest Set 22

1. Sivam invested some money in a scheme at the rate of 20% for 3 years. If he withdraws 40% of total amount and left remaining amount is rs.2304. What is total money which he invested at earlier.
2500
2400
3500
3200
4200
Option B
Let principal = 100x
SI = 100x * 20/100 * 3 = 60x
Total amount = 100x + 60x = 160x
remaining = 160x * 60/100 = 96x
96x = 2304
x = 24
He invested = 100x = 2400

2. Simple interest on rs.2750 for 2 years at certain rate of interest is rs.120 more than simple interest on rs.1500 for 3 years at same rate of interest. What is the rate of interest ?
12%
14%
15%
13%
18%
Option A
Let rate of interest = R%
(2750*R/100*2) – (1500*R/100*3) = 120
55 R – 45R = 120
10 R = 120
R = 12%

3. Simple interest on a certain sum of money at rate of 20% for 2 years is two times of the compound interest on rs.5000 for 2 years at the rate of 14% per annum. What is the sum on simple interest ?
8340
8000
12000
7490
14000
Option D
Rate of compound interest after 2 years = 14 + 14 + 14 * 14/100 = 29.96%
compound interest = 5000 * 29.96/100 = 1498
simple interest = 1498 * 2 = 2996
Let principal on simple interest = x
2996 = x * 20/100 * 2
x = 7490

4. A man invested an amount of rs.4800 for 3 years a certain rate of simple interest become rs.7248. If the rate of interest increases by 3%, what amount will rs.5000 becomes in 2 years ?
7200
6320
8450
8240
6830
Option A
Simple interest = 7248 – 4800 = 2448
2448 = 4800 * 3 * 12/100
R = 17%
Now rate of interest = 17 + 3 = 20%
Amount = 5000 * 120/100 * 120/100 = 7200

5. In how many years a sum will become four times itself at the rate of 12% per annum in simple interest ?
12 years
24 years
25 years
26 years
20 years
Option C
Let the principal = x
Amount = 4x
Simple interest = 4x – x = 3x
3x = x * 12/100 * T
T = 25 years.

6. A deposited rs.6800 in a bank at 8% per annum for 5 years simple interest. B deposited rs.8000 at 20% per annum for 2 years in compound interest. What is difference between compound interest and simple interest.
850
240
836
800
840
Option D
Simple interest = 6800 * 8/100 * 5 = 2720
By using successive,
20 + 20 + 20 * 20/100 = 44%
compound interest = 8000 * 44/100 = 3520
Difference = 3520 – 2720 = 800

7. A certain sum in simple interest becomes rs.6600 in 4 years and becomes rs.7400 in 6 years, then find the rate of interest.
4%
8%
20%
14%
18%
Option B
Simple interest for 2 years = 7400 – 6600 = 800
simple interest for 1 year = 400
simple interest for 4 years = 4 * 400 = 1600
sum = 6600 – 1600 = 5000
1600 = 5000 * R/100 * 4
R = 8%

8. The difference between compound and simple interests on a sum for 2 years at 15% per annum is 450. Find the sum.
12000
25000
20000
38000
35000
Option C
CI – SI = PR^2/100^2
450 = P * 225/10000
P = 20000

9. The population of a town increased by 25% p.a. If the present population is 50000. Find the population of town 3 years ago.
25600
24480
32540
24000
30340
Option A
Let the population of town 3 year ago = x
x * 5/4 * 5/4 * 5/4 = 50000
x = 50000 * 64/125
x = 25600

10. What is difference between compound interest and simple interest for 2 years on a principal of rs.4000 at the annual rate of 25% ?
340
125
250
350
300
Option C
Simple interest = 4000 * 25/100 * 2 = 2000
Rate of compound interest after 2 years = 25 + 25 + 25 * 25/100 = 56.25%
compound interest = 4000 * 56.25/100 = 2250
difference = 2250 – 2000 = 250