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%`

Explanation

let principal amoun be P.

Amount=P+simple interest

Amount=2P

simple interest=P

simple interest= `(P xx R xx T)/100=P`

T=10 yrs

so R=Rate =10%