What will be the ratio of simple interest earned by certain amount at the same rate of interest for 12 years and that for 28 years? Choose the correct choice from the following answers
A) 5 : 7
B) 4 : 7
C) 3 : 7
D) Data inadequate
E) None of these
Let the principal be P and rate of interest be R%.   ∴ Required Ratio = [(P×R×12/100) /(P×R×28/100)]=12PR/28PR=12/28=3:7   Answer 3 : 7
<result>C</result>
What will be the ratio of simple interest earned by certain amount at the same rate of interest for 12 years and that for 28 years?