Task: Question Answering
Input (English): Problem: the average weight of a group of boys is 30 kg . after a boy of weight 40 kg joins the group , the average weight of the group goes up by 1 kg . find the number of boys in the group originally ? 
Options: a ) 14 , b ) 5 , c ) 6 , d ) 7 , e ) 9
Output (English): e