If the simple interest on a certain sum of money for 7 years is one–fifth of the sum, then the rate of interest per annum is  Choices.
A) 4%	B) 2.50%	C) 6.20%	D) 5%	E) 2.85%
2.85%xplanation:   Let the Principal(P) be x   Then, Simple Interest(SI) = x/5   Time(T) = 7 years   Rate of interest per annum(R) = (100×SI)/PT   = (100 × (x/5)/(x × 7) = 20/7 = 2.85%   Answer: Option 2.85%
<result>E</result>
If the simple interest on a certain sum of money for 7 years is one–fifth of the sum, then the rate of interest per annum is