on a sum of money, simple interest for 2 years is rs 660 and compound interest is rs 696.30, the rate of interest being the same in both cases.  Choices:
A) 8 %
B) 9 %
C) 10 %
D) 11 %
E) none of these
<gadget id="calculator">696.3 - 660</gadget>
<output>36.3</output>

<gadget id="calculator">36.3 * 2</gadget>
<output>72.6</output>

<gadget id="calculator">72.6 / 660</gadget>
<output>0.11</output>

<gadget id="calculator">0.11 * 100</gadget>
<output>11</output>

<result>D</result>
on a sum of money, simple interest for 2 years is rs 660 and compound interest is rs 696.30, the rate of interest being the same in both cases.
multiply(divide(multiply(subtract(696.3, 660), 2), 660), const_100)
explanation : difference between c . i and s . i for 2 years = 36.30 s . i . for one year = 330 . s . i . on rs 330 for one year = 36.30 so r % = \ frac { 100 * 36.30 } { 330 * 1 } = 11 % answer : d