Task: Question Answering
Input (English): Problem: a is 1.5 times as fast as b . a alone can do the work in 30 days . if a and b work on alternative days , beginning with a , in how many days will the work be completed ? 
Options: a ) 23 , b ) 22 , c ) 21 , d ) 36 , e ) 25
Output (English): d