Question

A man borrows Rs.20000 at 10% per annum compound interest payable annually. If he repays Rs.5000 at the end of the first year and Rs.10000 at the end of the second year; how much should he pay at the end of the third year in order to clear the account? Find the answer correct to the nearest rupee.

Answer 1

For 1^st half year : P = Rs.2000, R = 10% and T = 1 year

Interest = Rs.`(20000 xx 10 xx 1)/(100)`
 =Rs.2000
Amount
= Rs.20000 + Rs.2000
= Rs.22000
Money paid at the end of 1^st half year = Rs.5000
Balance money for 2^nd half year
 =Rs.22000 - Rs.5000
= Rs.17000
For 2^nd half year : P = Rs.17000; R = 10% and T = 1 year

Interest = Rs.`(17000 xx 10 xx 1)/(100)`
 = Rs.1700
Amount
 = Rs.17000 + Rs.1700
 = Rs.18700
Money paid at the end of 2^nd half year = Rs.10000
Balance money for 3^rd half year 
= Rs.18700 - Rs.10000
 =Rs.8700
For 3^rd half year : P = Rs.8700; R = 10% and T = 1 year

Interest = Rs.`(8700 xx 10 xx 1)/(100)`
 = Rs.870
Amount
 = Rs.8700 + Rs.870
 =Rs.9570
A man should pay Rs.9570 at the end of 3^rd year to clear the account.