Compound interest earned on a sum for the second and the third years are Rs.1200 and Rs.1440 respectively. Find the rate of interest?	Select:  A) 80% p.a  B) 10% p.a  C) 20% p.a  D) 28% p.a  E) 30% p.a
Rs.1440 - 1200 = Rs.240 is the interest on Rs.1200 for one year.   Rate of interest = (100 * 240) / (100 * 1) = 20% p.a   Answer:20% p.a
<result>C</result>
Compound interest earned on a sum for the second and the third years are Rs.1200 and Rs.1440 respectively. Find the rate of interest?