Company A can set up the gymnasium for a banquet in 3 hours. Company B needs 5 hrs to do the same job. How long would it take them working together, to set up the gymnasium?

1 Answer
Jun 25, 2016

For problems like this, you need to consider how much work each individual (company in this case) can do in one hour.

Explanation:

#1/3 + 1/5 = 1/"time working together"#

#5/15 + 3/15 = 1/"time working together"#

#8/15 = 1/"time working together"#

#"time working together" = 15/8" hours" = 1 7/8" hours" = 1" hour, 52 minutes, 5 seconds"#

Hence, when company A and B work together, the gymnasium will be set up in 1 hour, 52 minutes and 5 seconds.