Compound interest earned on a sum for the second and the third years are Rs.12000 and Rs.13800 respectively. Find the rate of interest?
Choose one:
A) 15% p.a.
B) 22% p.a.
C) 20% p.a.
D) 24% p.a.
E) None of these.
Rs.13800 - 12000 = Rs.1800 is the interest on Rs.12000 for one year.   Rate of interest = (1800/12000) * 100= 
<gadget id="calculator">(1800/12000) * 100</gadget>
<output>15</output>
15% p.a   15% p.a.NSWER:15% p.a.
<result>A</result>
Compound interest earned on a sum for the second and the third years are Rs.12000 and Rs.13800 respectively. Find the rate of interest?