If the simple interest on a certain sum of money for 2 years is one–fifth of the sum, then the rate of interest per annum is
Choose the correct option:
A) 14%
B) 7%
C) 10%
D) 15%
E) 3%
Explanation:   Let the Principal(P) be x   Then, Simple Interest(SI) = x/5   Time(T) = 2 years   Rate of interest per annum(R) = (100×SI)/PT   = (100 × (x/5)/(x × 2) = 20/2= 
<gadget id="calculator">20/2</gadget>
<output>10</output>
10%   Answer: Option 10%
<result>C</result>
If the simple interest on a certain sum of money for 2 years is one–fifth of the sum, then the rate of interest per annum is