A sum of money invested at C.I. amounts to Rs. 800 in 3 years to Rs. 840 in 4 years. The rate of interest per annum is? Choose the correct option
A) 3	B) 2	C) 5	D) 7	E) 1
Explanation:   S.I. on Rs. 800 for 1 year = (840 - 800) = Rs. 40 Rate = (100 * 40)/(800 * 1)= 
<gadget id="calculator">(100 * 40)/(800 * 1)</gadget>
<output>5</output>
5%   Answer:5
<result>C</result>
A sum of money invested at C.I. amounts to Rs. 800 in 3 years to Rs. 840 in 4 years. The rate of interest per annum is?