Task: Question Answering
Input (English): Problem: a lent rs . 5000 to b for 2 years and rs . 3000 to c for 4 years on simple interest at the same rate of interest and received rs . 2640 in all from both of them as interest . the rate of interest per annum is ? 
Options: a ) 16 % , b ) 12 % , c ) 74 % , d ) 10 % , e ) 45 %
Output (English): b