Lisa an experienced shipping clerk can fill a certain order in 7 hours to a new clerk needs 8 hours to do the same job working together how long will it take to fill the order

In one hour Lisa can do 1/7 of the job, and in one hour the new clerk can do 1/8 of the job. Working together for one hour they can do (1/7) + (1/8) of the job.

Therefore when working together they will take 56/15 = 3.733 hours.

The answer is 3.733 hours or 3 hours and 44 minutes.