An amount doubles itself in 5 years simple interest. What is the rate of interest per year?

₹ 500 was invested at 12 % per annum simple interest and another certain sum of money invested at 10 % per annum simple interest . If the total interest on both the sum after 4 years is 480, the latter sum of money is

The sum of money that will yield Rs. 60 as simple interest at the rate of 6% per annum in 5 years is-

A sum of money at simple interest amount to Rs.4800 in 3 years and Rs.5600 in the 5 years. The sum is

The simple interest and the true discount on a certain sum for a given period and at a given rate are 25 and 20 respectively. The sum is 

Alipta got some amount of money from her father. In how many years will the ratio of the money and the interest obtained from it be 10:3 at the rate of 6% simple interest per annum?

If an amount doubles automatically in 8 years, then what is the interest rate?

Which amount will be Rs 520 in 5 years with simple interest and Rs 568 in 7 years?