If simple interest for 2 years for a sum is TK. 600 and compound interest for the same sum for 2 years and the same rate of interest is TK. 645, what will be the rate of interest?

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

How much interest is earned on TK. 2000 in 3 years at a rate of 5% per annum?

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

A sum of TK. 8000 grows to TK. 8800 in 4 years at simple interest. What is the amount of simple interest?

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

What is the amount of simple interest earned on TK. 8000 in 6 years at a rate of 9% per annum?

Find the time n for TK. 1000 to become TK. 1300 at a rate of 5%.

What is the simple interest earned on TK. 7500 in 3 years at 6% per annum?

A certain amount of money amounts to TK. 7200 in 3 years at 10% per annum. What is the principal amount?