Answer:
3 1/13
Explanation:
rate(time) of one pipe + rate(time) of the other pipe = 1 job
The rate would be the the number of jobs over the time
The rate of the first pipe is 1/5 and the rate of the second pipe is 1/8.
Together:
1/5t + 1/8t = I job
t(1/5 + 1/8) = 1
t(8/40 + 5/40) = 1
t(13/40) = 1 multiply each side by 40/13
t(40/13)(13/40) = 1(40/13)
t = 40/13
t = 3 1/13