Task: Question Answering
Input (English): Problem: a mixture contains milk and water in the ratio 7 : 3 . on adding 20 liters of water , the ratio of milk to water becomes 7 : 5 . total quantity of milk & water before adding water to it ? 
Options: a ) 90 , b ) 100 , c ) 110 , d ) 120 , e ) 140
Output (English): b