Two cars traveled equal distances in different amounts of time. car a traveled the distance in 4 h, and car b traveled the distance in 4.5 h. car b traveled 5 mph slower than car a.
how fast did car b travel?

The rate of Car A is x
The rate of Car B is x - 5

They travel the same distance. So we can make an equation:

4(x) = 4.5(x-5)

Solve for x.

4(x) = 4.5(x-5)
4x = 4.5x - 22.5

Subtract 4.5x on both sides

-0.5x = -22.5

Divide by -0.5 on both sides
x = 45

But we want the speed of Car B which is x - 5

So Car B's speed is 45 - 5 = 40

Your answer is 40