Question

A certain sum of money at simple interest becomes Rs. 1062 in 2 years and Rs. 1183.50 in 31⁄2 years. What is rate of interest per annum?

Answer 1

1183.50-1062 = 121.50 for (3.5-2) years i.e. 1.5 yrs

So for 1 year interest is

=> 121.5/1.5= Rs.81

For 2 yrs interest is

81*2= Rs.162

Then principal

1062 - 162= Rs. 900

Therefore, rate of interest per annum is 81/900*100 i.e  9%