Task: Question Answering
Input (English): Problem: the average age of a family of 5 members is 20 years . if the age of the youngest member be 10 years then what was the average age of the family at the time of the birth of the youngest member ? 
Options: a ) 13.5 , b ) 14 , c ) 15 , d ) 12.5 , e ) none
Output (English): d