Answer:
An equation that relates the speeds of the two legs of the trip
[tex]\frac{640}{x-40}+\frac{640}{x}=4[/tex]
Explanation:
Given, we have to use x to represent the speed on the second leg
Speed on first leg when increasing your speed by 40 mph will be (x-40)
Distance is given as 640 miles and time is calculated as
[tex]\text { Time }=\frac{\text { Distance travelled }}{\text { speed }}[/tex]
According to the question, increasing speed saved four hours
Therefore, the equation that relates the speeds of the two legs of the trip will be
[tex]\frac{640}{x-40}+\frac{640}{x}=4[/tex]