A sum of money was lent at 10% per annum, compounded annually, for 2 years. If the interest was compounded half - yearly, he would have received Rs.660.75 more. Find the sum.

The difference between simple interest and compound interest on a certain sum at $$ 12{1\over2}$$ % for 3 years is Rs 125. Find the sum.

A person invested Rs 3000 on compound interest for two years. If the rate of interest is the 25 % for the first year and 20 % for the second year. Then find the CI?

There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of Rs. 12,000 after 3 years at the same rate?

At what percent per annum will Rs. 3000 amounts to Rs. 3993 in 3 years if the interest is compounded annually?  

A sum of money becomes eight times in 3 years, if the rate is compounded annually. In how much time will the amount at the same compound rate become sixteen times? 

If the difference between the compound interest and simple interest on a certain sum at 5% per annum for 3 years is Rs.11.40, what is the approximate sum? 

The compound interest on Rs.16, 000 for 9 months at 20 % per annum, interest being compounded quarterly, is