At what rate percent per annum will a sum of money double in 8 years.	Select.
A) 12.5 % B) 12.9 % C) 18.5 % D) 11.5 % E) 12.3 %

Rationale: "explanation : let principal = p , then , s . i . = p and time = 8 years rate = [ ( 100 x p ) / ( p x 8 ) ] % = 12.5 % per annum . answer : a ) 12.5 %"
Answer: A