Question

A certain sum amounts to Rs. 5,292 in two years and Rs. 5,556.60 in three years, interest being compounded annually. Find: the original sum.

Answer 1

Let the sum of money = Rs. 100
Interest on it for 1^st year= 5% of Rs. 100 = Rs. 5
⇒ Amount in one year= Rs. 100 + Rs. 5 = Rs. 105
Similarly, amount in two years = Rs. 105 + 5% of Rs. 105
= Rs. 105+ Rs. 5.25
= Rs. 110.25
When amount in two years is Rs. 110.25, sum = Rs. 100
⇒ When amount in two years is Rs. 5,292,
sum = Rs. `[ 100 xx 5,292]/[110.25 ]` = Rs. 4,800.