It takes you 45 minutes to wash a car alone. Your friend can wash a car in 30
minutes. How long will it take you and
your friend to wash a car together? You
can use the work principle to find out!

37. 5 minutes in total.

So someone else had gave the correct answer, but I thought it wasn’t clear enough so I hope this helps.

Step-by-step explanation:

45 + 30 = 75.

But 75 cannot be a total of minutes... so therefore we divide 75 by 2

75 ÷ 2 = 37. 5

So it will take you and your friend a total of 37. 5 minutes to wash a car together.

Hope this helped