Question

. CAR WASH Shea and Tucker are washing their father's car. Shea can wash it by herself in 20 minutes. Tucker can wash it by himself in 30 minutes. 19 How long does it take them to wash the car if they work together?

Answer 1

12 minutes

Explanation:

First we figure out how much of a car each person can wash in 1 minute.

Shea can wash the car by herself in 20 minutes

Therefore, she can wash a car in 1 minute =
`(1)/(20)`

Tucker can wash a car in 30 minutes.

Tucker can wash the car in 1 minute =
`(1)/(30)`

Thus, in one minute together they wash a car

`(1)/(20)` +
`(1)/(30)` =
`(50)/(600)` =
`(1)/(12)`

In one minute together they can wash =
`(1)/(12)` of a car

Time needed to wash entire car together = 12 minutes.

It takes them 12 minutes to wash the car.