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?
Here's one method:
The least common multiple of
So for both of them working to fill one order would take:
To express in hours and minutes:
#99/20 = 80/20+19/20 = 4+(3*19)/(3*20) = 4+57/60#