SOLUTION: Jon recently drove to visit his parents who live 192 miles away. On his way there his average speed was 20 mph faster than on his way home. If Jon spent 8 hours driving, find the 2

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Question 757155: Jon recently drove to visit his parents who live 192 miles away. On his way there his average speed was 20 mph faster than on his way home. If Jon spent 8 hours driving, find the 2 rates.
Answer by LearnWithMajor(33) About Me  (Show Source):
You can put this solution on YOUR website!
x = rate of travel to parents, y = rate of travel home
On his way there his average speed was 20 mph faster than on his way home.
x+=+y+%2B+20
Jon spent 8 hours driving
Time equals distance divided by rate.
t = d/r
192%2Fx+%2B+192%2Fy+=+8 time for the trip to parents plus time to get home equals 8 hours
Now substituting y+20 in for x
192%2F%28y%2B20%29+%2B+192%2Fy+=+8
192y+%2B+192%28y%2B20%29+=+8y%28y%2B20%29
192y+%2B+192y+%2B+3840+=+8y%5E2+%2B+160y
8y%5E2+-+224y+-+3840+=+0
y%5E2+-+28y+-+480+=+0
%28y-20%29%28y%2B12%29=0
y = 20
x = y + 20 = 20 + 20 = 40