# Sue, an experienced shipping clerk, can fill a certain order in 9 hours. Felipe, a new clerk, needs 11 hours to do the same job. Working together, how long will it take them to fill the order?

##### 1 Answer

Jan 9, 2017

#### Explanation:

Here's one method:

The least common multiple of

In

So for both of them working to fill one order would take:

#99/20# hours.

To express in hours and minutes:

#99/20 = 80/20+19/20 = 4+(3*19)/(3*20) = 4+57/60#

That's