math help i never got how to do this

Mary takes 3 hours to mow the yard. It takes Sally 5 hours. How long would it take with them mowing it together? Give the exact decimal answer ???have no clue how

Glitter2008-07-31T17:32:23Z

Favorite Answer

It takes Mary 3 hours to complete the job. So in 1 hour, she would have completed 1/3 of the job.

It takes Sally 5 hours to complete the job. In 1 hour, she would have completed 1/5 of the job.

1/3 + 1/5
5/15 + 3/15
= 8/15

In 1 hour, working together, Mary and Sally would complete 8/15 of the job. To find out how many hours it takes, flip the fraction.

15/8 = 1.875 hours

It would take them 1.875 hours to mow the yard.

:)

?2008-07-31T17:23:16Z

one third plus one fifth equals one over x so try solving it that way