Answer:
45 mph
Step-by-step explanation:
Using the equation d = rt, we can rearrange the equation to be t = d/r
Since the amount of time was the same, we can set d/r equal to each other for both speeds.
Let x represent the average speed.
[tex]\frac{d}{r}[/tex] = [tex]\frac{d}{r}[/tex]
[tex]\frac{180}{x}[/tex] = [tex]\frac{200}{x+5}[/tex]
Cross multiply and solve for x:
200x = 180x + 900
20x = 900
x = 45
So, the average speed was 45 mph
