A sum of money invested at compound interest to Rs. 800 in 3 years and to Rs 850 in 4 years. The
rate on interest per annum is.  Choose the correct option:
A) 4.20% B) 50% C) 60% D) 6.25% E) 8.10%
Explanation:   S.I. on Rs 800 for 1 year = 50   Rate = (100*50)/(800*1)= 
<gadget id="calculator">(100*50)/(800*1)</gadget>
<output>25/4 = around 6.25</output>
6.25%   Answer: 6.25%
<result>D</result>
A sum of money invested at compound interest to Rs. 800 in 3 years and to Rs 850 in 4 years. The
rate on interest per annum is.