Question

the interest on a certain sum of money is 0.24 times of itself in 3 years find the rate of interest

Answer 1

Let p=100
Then I =24
Time=3 years
I=p*r*t/100
R=(24*100)/(100*3)
=8%p.a

Answer 2

For SI the rate is 8%. for CI the rate is 7.4%

1) Let the amount put be P.

2) Given Interest on the amount be 0.24P

3) Time duration is 3 years.

4) Assuming Simple Interest

SI = PRT/100

Substituting the values 0.24P = PR*3/100

Hence the rate of interest is 8% p.a.

5) Assuming Compound Interest

CI = $P((1+ \frac{R}{100})^T -1)$

Substituting the values :

0.24P = P$((1+ \frac{R}{100})^3 -1$)

R = $100( \sqrt[3]{1.24} - 1 )$

R = 7.4%p.a.