The sum of money at compound interest amounts to thrice itself in 3 years. In how many years will it be 9 times itself?  Choose the correct answer:
A) 5 B) 4 C) 3 D) 6 E) 7
100 ---- 300 --- 3   900 --- 3   ----   6 years   Answer: 6
<result>D</result>
The sum of money at compound interest amounts to thrice itself in 3 years. In how many years will it be 9 times itself?