at what rate per annum simple interest will a sum double it self in 2 years?

At what rate per cent per annum simple interest will a sum double itself in 10 years?

At what rate per cent per annum simple interest will a sum double itself in 10 years?

At what rate percentage per annum simple interest will a sum triple itself in 20 years.

At what rate of interest per annum will a sum double itself in 8 years ?

At what rate of simple interest a certain sum will be doubled in 12 years ?

At what rate of simple interest a certain sum will be doubled in 15 years?

At what rate of simple interest a certain sum will be doubled in 14 years

At a certain rate per annum , the simple interest on a sum of money for one year is Rs.260 and the compound interest on the same sum for two years is Rs. 540.80 . The rate of interest per annum is