Arun took a loan of Rs. 1400 with simple interest for as many years as the rate of interest. If he paid Rs.686 as interest at the end of the loan period, what was the rate of interest? Select the correct option.
A) 8%  B) 6%  C) 4%  D) 7%  E) 5%
Explanation :   Let rate = R%   Then, Time, T = R years   P = Rs.1400   SI = Rs.686   SI= PRT/100   ⇒686 = 1400 × R × R /100   ⇒686=14 R^2   ⇒49=R^2   ⇒R=7   i.e.,Rate of Interest was 7%   Answer : Option 7%
<result>D</result>
Arun took a loan of Rs. 1400 with simple interest for as many years as the rate of interest. If he paid Rs.686 as interest at the end of the loan period, what was the rate of interest?