# Quantitative Aptitude: Simple/Compound Interest Set 10

1. A lent Rs. 6000 to B for 3 years and Rs. 7000 to C for 4 years on simple interest at the same rate of interest and received Rs. 4600 in all from both of them as interest. The rate of interest per annum is:
12%
10%
8%
9%
None
Option B
Solution:
Let the rate of interest be r.
(6000*r*3)/100 +(7000*r*4)/100=4600
180r+280r=4600
460r=4600==>r=10%.
2. A certain amount earns simple interest of Rs. 1950 after 6 years. Had the interest been 3% more, how much more interest would it have earned?
Rs55
Rs62
Rs80
None
Option D
Solution:
3. A person borrows Rs. 6000 for 2 years at 6% p.a. simple interest. He immediately lends it to another person at 7 3/5 p.a for 2 years. Find his gain in the transaction per year.
Rs192
Rs156
Rs86
Rs95
None
Option C
Solution: For 2years the gain is
(6000*38*2)/100*5 –(6000*6*2)/100
912-720=Rs192.
Then for 1 year 192/2=Rs86.
4. Find the compound interest on Rs. 1000 at the rate of 20% per annum for 18 month when interest is compounded half yearly.
Rs662
Rs545
Rs620
Rs568
None
Option A
Solution:
Principal, P = Rs. 2000
Compound rate, R = 20% per annum = 20/2 = 10% half-yearly
Time = 18 month = 3 half-years
Amount,
A = {P*[1+ (R/100)] n }
= {2000*[1+(10/100)] 3}
= {(2000*11*11*11/10*10*10)}
A = Rs. 2662
compound interest = Rs. 662.
5. A sum of Rs. 725 is lent in the beginning of a year at a certain rate of interest. After 8 months, a sum of Rs. 362.50 more is lent but at the rate twice the former. At the end of the year, Rs. 33.50 is earned as interest from both the loans. What was the original rate of interest?
2.5%
3.46%
4.25%
3.5%
None
Option B
Solution:
Let rate of interest be r. New r =2r, n=1/3years(4month)
(725*r*1)/100 + (362.5*2r*1)/100*3 = 33.50
(2175+725)r=33.5*100*3
2900r=10050
R=3.46%.
6. What is the rate of simple interest for the first 4 years if the sum of Rs. 360 becomes Rs. 540 in 9 years and the rate of interest for the last 5 years is 6%?
4%
10%
8%
5%
None
Option D
Solution:
Interest for the last 5 years = PTR/100;
= 360*5*6/100 = Rs. 108.
Interest for year = 540-360 = 180;
So, interest for first four years = 180-108 = Rs. 72;
Now, rate for first four years = (72*100)/360*4;
= 5%.
7. In what time will the simple interest on Rs. 1000 at 3% per annum be the same as that on Rs. 1500 at 6% per annum in 3 years?
6years
8years
9years
5years
None
Option C
Solution:
Let time is n years.
(1000*3*n)/100 = (1500*6*3)/100
n=9years.
8. Krish invested an amount of Rs. 6000 in a fixed deposit scheme for 2 years at compound interest rate 5 %p.a. How much amount will Krish get on maturity of the fixed deposit?
Rs6615
Rs6540
Rs6872
Rs5875
None
Option A
Solution:
Amount=6000*(1+5/100)2
=6000*21/20*21/20
=Rs 6615.
9. A sum of money placed at compound interest doubles itself in 4 years. In how many years will it amount to 8 times?
10years
12years
8years
9years
None
Option B
Solution:
x becomes 2x in 4years
Then x becomes 8x in ?
2x…………………… 4
8x(2*2*2)……….. ?
2x………………….. 4
23…….. ?
Short cut=multiply years with power=4*3=12years.
10. Divide Rs. 6000 into two parts so that simple interest on the first part for 2 years at 6% p.a. may be equal to the simple interest on the second part for 3 years at 8% p.a.
Rs4000,Rs2000
Rs3500,Rs2500
Rs2300,Rs3700
Rs3200,Rs2800
None
Option A
Solution:
Let 1st part be x and 2nd part be 6000-x.
(X*2*6/100) = ((6000-x)*3*8)/100
12x = 144000- 24x
36x = 144000
x = 144000/36 = Rs. 4000.
1st part = Rs. 4000
2nd part = Rs. 2000.

## 2 Thoughts to “Quantitative Aptitude: Simple/Compound Interest Set 10”

1. Balaji Radhakrishnan

GOOD HELP

2. Tapan

madam please chake question no 4. principle in question is 1000 but in solution 2000