Question

Emily washes a car in 6 minutes. Larissa can wash that same car in 8

minutes. How long can both of them wash the car together?

Answer 1

It takes Emily 6 minutes to wash the car. This means he washes 16
1
6
of the car per minute.Larissa therefore washes 18
1
8
of the car per minute. Working together, they both wash 16+18
1
6
+
1
8
of the car, or 724
7
24
of the car each minute. This means that it takes 247
24
7
minutes to wash the entire car — or 3 minutes, 25.714285... seconds total.