A sum of Rs. 2500 amounts to Rs. 3500 in 4 years at the rate of simple interest. What is the rate of interest?
Choose the correct choice from the following answers:
A) 7%
B) 9%
C) 5%
D) 6%
E) 10%
S.I. = (3500- 2500) = Rs. 1000   Rate = (100 * 1000) / (2500* 4)= 
<gadget id="calculator">(100 * 1000) / (2500* 4)</gadget>
<output>10</output>
10%   Answer: 10%
<result>E</result>
A sum of Rs. 2500 amounts to Rs. 3500 in 4 years at the rate of simple interest. What is the rate of interest?