SOLUTION: Please help me solve this story problem--I am lost :( You jog at 6 miles per hour for 5 miles, then you drive another 5 miles in a car. With what average speed must you drive if

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Question 1064882: Please help me solve this story problem--I am lost :( You jog at 6 miles per hour for 5 miles, then you drive another 5 miles in a car. With what average speed must you drive if your average speed for the entire 10 miles is to be 10.8 miles per hour?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
             SPEED      TIME      DISTANCE

On Foot      6          5/6         5

By Car       r          5/r         5

Total                 5/6+5/r      10

Distance divided by time is rate.
10%2F%285%2F6%2B5%2Fr%29=10.8


%285%2F6%2B5%2Fr%29%2810.8%29=10

1%2F6%2B1%2Fr=5%2F27

Multiply left and right by 54r.
9r%2B54=10r
highlight%28r=54%29