(a) A certain sum becomes double in 3 years, find the rate of interest.
(b) Find the simple interest on Rs. 8900 for `2(1)/(2)` years at the rate of `18%` p.a.

A certain sum becomes doubled in 5 years. Find the rate of interest.

A certain sum becomes Rs. 2400 in 10 years at the rate of 2% per annum under simple interest. Find the sum.

A certain sum of money doubles itself & number of years is equal to rate of interest. Find the rate of interest.

A sum becomes 1.6 times of itself in five years at simple rate of interest. Find rate of interest per annum?

A certain sum of money becomes Rs 2100 in 4 years and Rs 2550 in 7 years. Find the rate of simple interest per annum.

If simple interest on a certain sum of money for 4 years at 5% p.a. is same as the simple interest on Rs. 560 for 10 years at the rate of 4% p.a. then find the sum of money.