A Sum at compound interest amounts to Rs.7500 in 2 years and to Rs.9000 in 3 years then rate per annum is Choose the correct choice from the following:
A) 11%
B) 12%
C) 15%
D) 20%
E) 22%
1500/7500 *100= 
<gadget id="calculator">1500/7500 *100</gadget>
<output>20</output>
20%   ANSWER:20%
<result>D</result>
A Sum at compound interest amounts to Rs.7500 in 2 years and to Rs.9000 in 3 years then rate per annum is