Question

A certain sum of money at compound interest becomes Rs.7396 in 2 years and Rs. 7950.70 in 3 years. Find the rate of interest.

Answer 1

Amount in 3years = Rs 7950.70 
Amount in 2 years= Rs 7396.00 
Interest for 3rd year =Rs 554.70 
Principal for 3rd year=Rs 7396 
Time = 1year 
Rate = (Interest *100)/ Principal*Time 
= 554.70*100 /7396* 1 
= 55470/ 7396 = 7.5% 
Let sum of money = x 
Amount = Rs 7396 
Time = 2 years 
then Amount = Principal(1+R/100)^T 
7396 = x (1+7.5/100)^2 
x =Rs 7396 /(43/40)^2 
=Rs 7396 *40*40
=Rs 6400