How long will it take a sum of money invested at 5% p.a. S.I. to increase its value by 40%?  Choose the correct answer
A) 6 years B) 7 years C) 8 years D) 9 years E) None
Sol.   Let the sum be x. Then, S.I. = 40% of x = 2x/5; Rate = 5%.   ∴ Time = [100 * 2x/5 * 1/x*5] = 8 yea   Answer 8 years
<result>C</result>
How long will it take a sum of money invested at 5% p.a. S.I. to increase its value by 40%?