SOLUTION: It took Joe 10 hours to drive to a football game. On the way home he was able to increase his average speed by 15mph and make the return drive in only 7 hours. Find his average spe

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Question 1051696: It took Joe 10 hours to drive to a football game. On the way home he was able to increase his average speed by 15mph and make the return drive in only 7 hours. Find his average speed on the return drive
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Constant Travel Rate Rule, RT=D 

                 SPEED             TIME          DISTANCE
GOING             r                 10             d
BACK             r+15                7             d


system%28%28r%29%2810%29=d%2C%28r%2B15%29%287%29=d%29

highlight%2810r=7%28r%2B15%29%29

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

It took Joe 10 hours to drive to a football game. On the way home he was able to increase his average speed by 15mph and make the return drive in only 7 hours. Find his average speed on the return drive 
Let return speed be S

Then outbound speed = S - 15

We then get the following DISTANCE equation: 10(S - 15) = 7S

Solve for S to find return speed

That's all....Very, very simple...nothing COMPLEX!