A sum of Rs. 2000 amounts to Rs. 4000 in two years at compound interest. In how many years does the same amount becomes Rs. 8000. 

A person can buy a refrigerator for Rs.15,850 on cash payment or in installments for every year at 10% p.a for four years compounded annually. What is the approximate annual installment that he should pay?

A bank pays half-yearly compound interest at the rate of 5% p.a. . A person deposited Rs 1600 on January 1 and a similar amount on July 1 . Explain how much interest will be paid by the bank at the end of the year.

A sum amounts to ₹ 6480 in 4 years and ₹ 9600 in 8 years when it is compounded annually. Find the sum?

What will be compound interest on a sum of Rs. 1000 at the rate of interest 10% after 5 years?