How long will it take a sum of money invested at 5% p.a. S.I. to increase its value by 100%?	Choose the correct choice
A) 15 years  B) 16 years  C) 25 years  D) 20 years  E) 18 years
Sol.   Let the sum be x. Then, S.I. = 100% of x = x; Rate = 5%.   âˆ´ Time = [100 * 2x/5 * 1/x*5] = 20 years.   Answer: 20 years
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How long will it take a sum of money invested at 5% p.a. S.I. to increase its value by 100%?