Question Description
Lewiston and Vernonville are 128 miles apart. A car leaves Lewiston traveling towards Vernonville, and another car leaves Vernonville at the same time, traveling towards Lewiston. The car leaving Lewiston averages 10 mph more than the other, and they meet after 1 hour and 36 minutes. What are the average speeds of the cars?

Final Answer

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Distance = 128 miles
Let speed of the car leaving Vernonville be x mph
So the speed of the car that leaves Lewiston is (x + 10) mph
So their relative speed is x + x + 10 = (2x + 10); since they are travelling in opposite direction.
Time taken to meet = Distance / Relative Speed
T = 1 hr 36 min = 1.6 hr
1.6 = 128/(2x + 10)
1.6(2x + 10) = 128
3.2x + 16 =128
3.2x =112
x = 35 mph
So the average speeds for the cars are 35 mp and 45 mph.
