Task: Question Answering
Input (English): Problem: how many pounds of salt at 50 cents / lb must be mixed with 40 lbs of salt that costs 25 cents / lb so that a merchant will get 20 % profit by selling the mixture at 48 cents / lb ? 
Options: a ) 20 , b ) 15 , c ) 40 , d ) 60 , e ) 25
Output (English): d