Linear equation

Question

Working together, two persons finished a job in 28/11 days. Working alone, one person took 3days longer to do the job than the other. How long did each take to finish the job?

Answer 1

If one person takes X days to do a job and another takes Y days to do a job, the time it takes them to do it together is 

 

   XY .   

   X+Y

 

 So, if, in this problem, the job together takes 28/11 days, then X * Y = 28 and X + Y = 11.  X=7 and X=4 works here, and also fulfills the "3 days longer" part of the question.