Task: Question Answering
Input (English): Problem: 20 liters of a mixture is created by mixing liquid p and liquid q in the ratio 3 : 2 . how many liters of liquid q must be added to make the ratio 4 : 3 ? 
Options: a ) 1 , b ) 3 , c ) 5 , d ) 7 , e ) 9
Output (English): a