Task: Question Answering
Input (English): Problem: a certain elevator has a safe weight limit of 2,500 pounds . what is the greatest possible number of people who can safely ride on the elevator at one time with the average ( arithmetic mean ) weight of half the riders being 150 pounds and the average weight of the others being 160 pounds ? 
Options: a ) 7 , b ) 8 , c ) 9 , d ) 10 , e ) 16
Output (English): e