# Quantitative Aptitude: Simple/Compound Interest Set 21

1. The difference between compound interest and simple interest on rs.42000 at same rate of interest for 2 years is rs.945. What is the rate of interest ?
10%
15%
14%
20%
25%
Option B
945 = PR^2/100^2
945 = 42000 * R^2/10000
R^2 = 225
R = 15%

2. Rohit borrows rs.4000 at 10% on compound interest and at the end of the every year he paid rs.1000 back. How much amount should he pay at the end of the 3rd year to settlement all his debt ?
2500
3000
3240
3014
2480
Option D
total amount at the end of the 1st year = 4000 * 110/100 = 4400
After he paid rs.1000, remaining amount = 4400 – 1000 = 3400
total amount at the end of 2nd year = 3400 * 110/100 = 3740
After he paid rs.1000, remaining amount = 3740 – 1000 = 2740
total amount at the end of 3rd year = 2740 * 110/100 = 3014
At the end of 3rd year he paid 3014 to settlement his debt.

3. A man borrows rs.8000 for 3 years and he gave at 15%, 20% and 30% rate of interest for 1st year, 2nd year and 3rd year respectively. Then how much amount he paid at the end of 3rd years in compound interest ?
14435
14352
17250
19540
20450
Option B
Amount in 1st year = 8000 + (8000*15/100) = 9200
Amount in 2nd year = 9200 + (9200*20/100) = 11040
Amount in 3rd year = 11040 + (11040 * 30/100) = 14352

4. What is the compound interest on rs.8600 at 20% p.a. for 1 years, compounded half yearly.
2240
2420
1440
1806
1425
Option D
Rate of interest for 1 year = 20%
rate of interest for half year = 10%
by applying successive,
10 + 10 + 10 * 10/100 = 21%
compound interest = 8600 * 21/100 = 1806

5. Shivam invested a certain amount at the rate of 14% for 4 years in simple interest and after 4 years he obtained a total simple interest of rs.5600. If invested the same amount at the same rate of interest for 2 years in compound interest then how much interest would he have obtained ?
3220
2996
2834
2450
2830
Option B
Let principal be rs. x
= x * 14/100 * 4 = 5600
x = 5600 * 100/56 = 10000
by applying successive, rate of compound interest = 14 + 14 + 14 * 14/100 = 19.96%
compound interest = 10000 * 29.96/100 = 2996

6. The difference between simple interest and compound interest on a certain sum at 20% rate of interest for 2 years is 500. What is difference between simple interest and compound interest for 1st year, if interest is compounded half-yearly ?
120
180
125
150
190
Option C
500 = PR^2/100^2
500 = P * 400/10000
P = 12500
simple interest for 1st year = 12500 * 20/100 = 2500
Rate of interest for compound half yearly = 20/2 = 10%
by apply successive method,
rate of CI = 10 + 10 + 10 * 10/100 = 21%
compound interest = 12500 * 21/100 = 2625
Difference = 2625 – 2500 = 125

7. On a certain sum of money simple interest occurred after 4 years is rs.4800 and compound interest occurred after 2 years is rs.2580. If rate of interest in both cases are same, find the principal amount ?
12000
8000
14000
18000
20000
Option B
SI after 4 years = 4800
SI for 1 year = 4800/4 = 1200
SI for 2 years = 2400
CI for 2 years = 2580
by applying SI and CI ratio formula,
SI/CI = 200/200 + r
2400/2580 = 200/200 + r
r = 15%
Let principal = rs. x
x * 15/100 * 4 = 4800
x = 4800*100/60 = 8000

8. What is difference between compound interest and simple interest for 2 years at the rate of 20% on a principal of rs.8500 ?
240
520
340
624
125
Option C
SI for 2 years = 8500 * 20/100 * 2 = 3400
by applying successive
rate of compound interest after 2 years = 20 + 20 + 20 * 20/100 = 44%
CI = 8500 * 44/100 = 3740
Difference = 3740 – 3400 = 340

9. If a money get tripled in 5 years on a certain rate of simple interest, then find the rate of interest ?
20%
40%
48%
45%
25%
Option B
let principal = rs. x
amount = 3 * x = 3x
simple interest = 3x – x = 2x
2x = x * R/100 * 5
R = 40%

10. Shiva invested rs. X for 4.5 years at the rate of 20% p.a. on simple interest. If he received rs.2520 as interest, then what is the value of X ?
2800
1700
3400
4600
3800
Option A
2520 = X * 20/100 * 4.5
X = 2800