In how many years will a sum of money double itself at 10% per annum?
Answers:
A) 2 years 4 months  B) 4 years 2 months  C) 8 years 4 months  D) 10 years 8 months  E) None
Sol.   Let sum = x. Then, S.I. = x   ∴ Time = [100 * S.I. / P*R] = [100 * x / x * 12] years   = 8 1/3 years = 8 years 4 months.   Answer 8 years 4 months
<result>C</result>
In how many years will a sum of money double itself at 10% per annum?