An experienced shipping clerk can fill a certain order in 4 hours. A new clerk needs 5 hours to do the same job. Working together, how long will it take for them to fill the order?

If they work together, they will take 2 2/9 hours to fill the order

Step-by-step explanation:

An experience clerk can fill a certain order in 4 hours

A new clerk needs 5 hours.

How long will it take for them to fill the order?

The first step, find how much order they can complete in an hour

I will give an experieced clerk as A and the new clerk as B

A can finish 1/4 order in an hour

B can finisih 1/5 order in an hour

Second, if they work together, so

(1/4 + 1/5) order will be done in an hour

1/4 + 1/5 = 5/20 + 4 / 20 = 9/20

To complete the whole task, it will take:

= 20/20 or 1 : 9/20

= 1 x 20/9

= 2 2/9 hour