A sum of money amounts to Rs.9800 after 5 years and Rs.12005 after 8 years at the same rate of simple interest. The rate of interest per annum is  Choose the correct choice from the following answers:  A) 15%  B) 12%  C) 8%  D) 7%  E) 5%
Explanation :   Simple Interest for 3 years = (Rs.12005 - Rs.9800) = Rs.2205   Simple Interest for 5 years = 22053×5=Rs.3675   Principal(P) = (Rs.9800 - Rs.3675) = Rs.6125   R = 100×SI/PT   =100×3675/6125×5   =12%   Answer : Option 12%
<result>B</result>
A sum of money amounts to Rs.9800 after 5 years and Rs.12005 after 8 years at the same rate of simple interest. The rate of interest per annum is