word problem

Question

. P can complete a task in ydays while Q takes y+12 days to do the same task.
(a). What fraction of the task can each of them complete in a day?
(b). If both of them work together, they can complete the task in 8 days. Find y.

Answer 1

(a)

In one day

P does 1/y of the job

Q does 1/(y + 12) of the job

 

(b)

8/y + 8/(y + 12) = 1

8(y + 12) + 8y = y(y + 12)

 

Now solve for y.