# 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?

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:

$\frac{1}{3} + \frac{1}{5} = \frac{1}{\text{time working together}}$

$\frac{5}{15} + \frac{3}{15} = \frac{1}{\text{time working together}}$

$\frac{8}{15} = \frac{1}{\text{time working together}}$

$\text{time working together" = 15/8" hours" = 1 7/8" hours" = 1" hour, 52 minutes, 5 seconds}$

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