SOLUTION: 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.

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Question 861234: 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 miles per hour more than the other, and they meet after 1hour and 36 minutes. What are the average speeds of the cars?
The car leaving Lewiston averages ??? mph
The care Vernonville averages ??? mph
I would be eternally grateful if you could help.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The easier way to do this is to think of one car ( either one )
as standing still and the other car
as moving at the sum of their speeds
---------------------------------
Let +s+ = the speed of the Vernonville to Lewiston car
+s+%2B+10+ = the speed of the Lewiston to Vernonville
Convert time to hours
+36%2F60+=+.6+
+1+%2B+.6+=+1.6+
-----------------
+128+=+%28+s+%2B+s+%2B+10+%29%2A1.6+
+128+=+%28+2s+%2B+10+%29%2A1.6+
+2s+%2B+10+=+128+%2F+1.6+
+2s+%2B+10+=+80+
+2s+=+70+
+s+=+35+
+s+%2B+10+=+45+
----------------
The speed of the Vernonville to Lewiston car is 35 mi/hr
The speed of the Lewiston to Vernonville is 45 mi/hr
check:
+d%5B1%5D+=+35%2A1.6+
+d%5B1%5D+=+56+
and
+d%5B2%5D+=+45%2A1.6+
+d%5B2%5D+=+72+
+d%5B1%5D+%2B+d%5B2%5D+=+56+%2B+72+
+d%5B1%5D+%2B+d%5B2%5D+=+128+
OK
OK