Task: Question Answering
Input (English): Problem: mixture a is 10 percent alcohol , and mixture b is 40 percent alcohol . if the two are poured together to create a 4 - gallon mixture that contains 20 percent alcohol , approximately how many gallons of mixture a are in the mixture ? 
Options: a ) 1.6 , b ) 1.7 , c ) 1.8 , d ) 1.9 , e ) 2.0
Output (English): a