Question

At what rate of interest per annum will an amount get double in 16 years? A. 25/4% B. 12% C. 15% D. 8%

Answer 1

i think it is a) 25/4%

Answer 2

Let P =100 , & A = 200
then  Amount = P + Pnr/100
              200  = 100 + 100 *16*r/100
             200 - 100 = 16r
             100    =  16r
So, r = 100/16
      r = 25/4%