SOLUTION: Lewiston and Vernonville are 144 miles apart. A car leaves traveling towards Vernonville, and another car leaves Vernonville at the same time, traveling towards Lewiston . T
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Question 1164426: Lewiston and Vernonville are 144 miles apart. A car leaves traveling towards Vernonville, and another car leaves Vernonville at the same time, traveling towards Lewiston . The car leaving averages 10 miles per hour more than the other, and they meet after 1 hour and 36 minutes. What are the average speeds of the cars? Answer by ikleyn(52772) (Show Source):
Let u be the rate of the slower car (in mph).
Then the rate of the faster car is (u+10) mph.
The total distance equation is
144 = , (1)
where represents the time of 1 hour and 36 minutes.
Since = = , you simplify equation (1)
144 = .
Next, multiply both sides by 5
720 = 8u + 8*(u+10)
90 = u + (u + 10)
90 - 10 = 2u
80 = 2u
u = 80/2 = 40.
ANSWER. The slower car rate is 40 mph; the faster car rate is 40+10 = 50 mph.
