How long will it take a sum of money invested at 20% p.a. S.I. to increase double the value?	Answers.
A) 12 years. B) 8 years. C) 15 years. D) 13 years. E) 10 years.
Sol.   Let the sum be x. Then, S.I. = 200% of x = 2x; Rate =20%.   âˆ´ Time = [100 * 2x/5 * 1/x*5] = 10 years.   Answer 10 years.
<result>E</result>
How long will it take a sum of money invested at 20% p.a. S.I. to increase double the value?