At what rate percent per annum will a sum of money double in 9 years.  Answers.
A) 12.5%
B) 13.5%
C) 11.5%
D) 11.1%
E) 21.5%
Let principal = P, Then, S.I.=P and Time=8 years   Rate = [(100 x P)/ (P x 9)]% = 11.1% per annum. Answer: 11.1%
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At what rate percent per annum will a sum of money double in 9 years.