SOLUTION: During my trip to work, I spent 3/4 of the time driving on the highway, during which I covered 5/6 of the distance. My average speed on the highway was 60 miles per hour. What are
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Question 766839: During my trip to work, I spent 3/4 of the time driving on the highway, during which I covered 5/6 of the distance. My average speed on the highway was 60 miles per hour. What are the possible values of my average speed, in miles per hour, during the time I was not on the highway? Answer by josgarithmetic(39618) (Show Source):
You can put this solution on YOUR website! h is total time
d is total distance
ROAD______________speed_______time___________distance
Highway___________60_________(3/4)h_________(5/6)d
NonHighway________(___)______(1/4)h_________(1/6)d
Try making two equations using rate times time equals distance: and ; this last equation gives an expression for unknown r.
But we still have three variables and two equations, just one is rearranged.
This seems an open-ended problem. Use the highway equation to eliminate either the h or the d in the r equation. You might want to pick an arbitrary value for h or d.
Work with the highway equation....
So you can form the equation
No longer seems so open-ended. Solution method felt strange, but result is very clear.
With that result r=36 mph, you can evaluate possible averages of highway and nonhighway speeds.
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