Task: Question Answering
Input (English): Problem: a marketing firm determined that , of 200 households surveyed , 80 used neither brand r nor brand b soap , 60 used only brand r soap , and for every household that used both brands of soap , 3 used only brand b soap . how many of the 200 households surveyed used both brands of soap ? 
Options: a ) 15 , b ) 20 , c ) 30 , d ) 40 , e ) 45
Output (English): d