Task: Question Answering
Input (English): Problem: machine a takes 50 hours to complete a certain job and starts that job at 6 am . after four hour of working alone , machine a is joined by machine b and together they complete the job at 1 pm . how long would it have taken machine b to complete the job if it had worked alone for the entire job ? 
Options: a ) 9 , b ) 88.88 , c ) 4.88 , d ) 2.88 , e ) 3.88
Output (English): e