Answer:
12 minutes
Step-by-step 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 =
Tucker can wash a car in 30 minutes.
Tucker can wash the car in 1 minute =
Thus, in one minute together they wash a car
+
=
=
In one minute together they can wash = of a car
Time needed to wash entire car together = 12 minutes.
It takes them 12 minutes to wash the car.