A sum of money invested at compound interest to Rs. 800 in 3 years and to Rs 860 in 4 years. The
rate on interest per annum is. Choose one: A) 4.5% B) 5% C) 6% D) 7.5% E) 8%
Explanation:   S.I. on Rs 800 for 1 year = 60   Rate = (100*60)/(800*1)= 
<gadget id="calculator">(100*60)/(800*1)</gadget>
<output>15/2 = around 7.5</output>
7.5%   Answer: 7.5%
<result>D</result>
A sum of money invested at compound interest to Rs. 800 in 3 years and to Rs 860 in 4 years. The
rate on interest per annum is.