Task: Question Answering
Input (English): Problem: in an apartment building that has 490 units , 4 out of every 7 units are currently rented , including 1 / 3 of the one - bedroom units . if , of the rented apartments , there is a 6 : 1 ratio of two - bedroom units to one - bedroom units , and the building only consists of two - bedroom and one - bedroom units , how many two - bedroom units are not rented ? 
Options: a ) 50 , b ) 70 , c ) 100 , d ) 130 , e ) 140
Output (English): d