A sum of money doubles itself in 20 years. What is the rate of interest?

If the amount of TK. 5000 becomes TK. 6000 in 4 years at simple interest, what is the amount of simple interest?

A sum of TK. 2000 is invested for 2 years at a simple interest rate of 9%. What is the total amount after the investment period?

A sum of money earns TK. 2400 as simple interest at 5% per annum over 4 years. What is the principal amount?

If a certain amount of money amounts to TK. 2000 in 5 years at 10% per annum, what is the principal amount?

A certain sum amounts to TK. 3000 in 3 years and TK. 4000 in 5 years at simple interest. What is the rate of interest per annum?

A sum of TK. 2500 grows to TK. 3250 in 5 years at simple interest. What is the rate of interest?

Mr. John deposited TK. 40,000 in a bank and earned simple interest at 7% per annum for two years. Calculate the interest earned at the end of the period.

How much interest does TK. 4000 earn in 8 years at a rate of 7% per annum?

An amount of TK. 4500 is invested at a simple interest rate of 12% per annum. If the interest earned is TK. 2160, how many years was the money invested?