In how many years will a sum of money doubles itself at 5% per annum on simple interest?	Choose the correct choice from the following answers.
A) 27%
B) 70%
C) 29%
D) 20%
E) 50%
P = (P*5*R)/100   R = 20%   Answer: 20%
<result>D</result>
In how many years will a sum of money doubles itself at 5% per annum on simple interest?