Question

At what rate of compound interest will a sum of Rs 640 amount to Rs 1250 in 3 years?

Answer 1

Step-by-step explanation:

t what rate of compound interest will a sum of Rs 640 amount to Rs 1250 in 3 years?

Answer 2

Compound interest  rate will be $25\%$  .

Step-by-step explanation:

Compound interest  rate will be

Given:

In 3 years ,Sum of Rs 640 amount to Rs 1250.

To Find:

Compound interest rate.

Formula Used:      

$A=M(1+\frac{p}{100} )^{q}$     --------------------------------- formula no.01

A =  total amount of money after compounding period

M= the original amount or initial amount

p=  the annual interest rate

p =  the number of years

Solution:

As given : In 3 years ,Sum of Rs 640 amount to Rs 1250.

M=640 Rs.  ,    A= 1250 Rs.      and   q= 3 years

Applying formula no. 01 and putting the values of M,A and q in formula,we get.

$A=M(1+\frac{p}{100} )^{q}$

$1250=640(1+\frac{p}{100} )^{3}$

$\frac{1250}{640} =(1+\frac{p}{100} )^{3}$

$\frac{125}{64} =(1+\frac{p}{100} )^{3}$

$(\frac{5}{4} )^{3} =(1+\frac{p}{100} )^{3}$

$\frac{5}{4} =(1+\frac{p}{100} )$

$\frac{p}{100} =\frac{5}{4} -1$

$\frac{p}{100} =\frac{1}{4}$

$p=25\%$

Thus,Compound interest  rate will be $25\%$.