Question

It takes Natalie five hours to tar a roof. Imani can tar the same roof in ten hours. How long would it take them if they worked together? Round your answer to the nearest hundredth. A. 3.51 hours B. 2.77 hours C. 3.33 hours D.4.3 hours

Answer 1

C. 3.33 hours

Explanation:

Use the algebra work equation:

`(1)/(tb)` =
`(1)/(t1)` +
`(1)/(t2)`, where tb is the time to work together, t1 is the time it takes one person, and t2 is the time it takes the other person

Plug in the values we know:

`(1)/(tb)` =
`(1)/(5)` +
`(1)/(10)`

`(1)/(tb)` =
`(4)/(20)` +
`(2)/(20)`

`(1)/(tb)` =
`(6)/(20)`

20 = 6tb

3.33 = tb

So, it would take them 3.33 hours when working together.