There is 80% increase in amount in 5 years at simple interest. What will be the compound interest of Rs. 20,000 after 3 years at the same rate?

Surekha borrowed a sum of money and returned it in two equal annual instalments of ₹5,547 each. If the rate of interest was $$7{1\over 2}\%$$ p.a. compounded yearly, then the total interest paid by her was:

A sum of ₹14,375, when invested at r% interest per year compounded annually, amounts to ₹16,767 after two years. What is the value of r?

The compound interest on 12000 for 9 months at 20 % per annum , interest being compounded quarterly is 

A woman invests Rs. 2000 at the start of each year at 5% compound interest per annum. How much will her investment be at the end of the 2^nd year?

The amount on ₹ 25000 in 2 years at annually compound interest. if the rate for the successive years be 4 % and 5 % per annum respectively is 

A borrowed Rs.1500 at 4% per annum and Rs.1400 at 5% per annum for the same period. He paid Rs.390 as total interest. Find the time for which he borrowed 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?