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

At what rate percent per annum simple interest will a sum double itself in 10 years? (a) 8% (b) 10% (c) 12% (d) 12 1/2%

At what rate percent per annum simple interest will a sum double itself in 10 years? 8% (b) 10% 12% (d) 12(1)/(2)%

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

At what rate per cent per annum simple interest will a sum treble itself in 16 years?

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

At what rate percentage per annum simple Interest will a sum triple itself in 16 years?

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 Rs. 66000 amount to Rs. 72720 in 2 years?

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

What will be the rate per cent interest when a sum doubles itself in 6 years ?