Simple and Compound Interest

At what percentage of simple interest ,sum of money will double itself in 7 years?

Sankar borrowed some money at the rate of 4% pa for the first 4 years,6% for the next 3 years and 7% for the next 10 years.If the total interest paid by him is Rs.8528,how much money did he borrow?

A sum of money trebles itself in 16 years.In how many years it would become double itself in how many years?

Babu takes a loan Rs.2000 at 5% simple interest.He returns Rs.1000 at the end of 1 year.How much amount he should pay to clear the due in 2 years.

If the annual rate of simple interest increases from 10% to 12(1/2)%,annual income increases by 2500 then the principal(Rs)

Arjun took a certain sum as loan from Bank at a rate of 10% simple interest per annum. Arjun lends the same amount to Bala at 14% simple interest per annum. If at the end of five years. Arjun made profit of Rs.800 from the deal, how much was the original sum ?

The simple interest accrued on a sum of certain principal is Rs.1000 in 4 years at the rate of 6% p What would be the SI accrued on thrice of that principal at the rate of 4%pa in 3yrs.

A sum of money amounts to Rs. 1500 after 3 years and Rs.2000 after 5 years at the same rate of SI. Find the rate of interest per annum ?

At what interest per annum will a sum of money double in 14 yrs ?

A sum of Rs.1500 is lent out into 2 parts, one at 10% and another one at 6%. If the total annual income is Rs.100, Find the money lent at each rate