A sum of money invested at simple interest triples itself in 8 years and becomes n times in 20 years. What is the value of n?

A sum of money invested at compound interest amounts to Rs 4624 in 2 years and to Rs 4913 in 3 years. The sum of money is

At what simple interest rate percent per annum will a sum of money double in 8 years?

A sum doubles itself in 2.5 years at compound interest. In how many years will it become eight times?

What is the amount for a sum of money Rs.7500 at 6% rate of interest C.I. for 2 years?

On lending a certain sum of money on C.I. one gets Rs.9050 in 2 years and Rs.9500 in 3 years. What is the rate of interest?