SOLUTION: On Monday, Roger drove to work in 2 hours. On Tuesday, he averaged 15 miles per hour more, and it took him 30 minutes less to get to work. How far (in miles) does he travel to work

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Question 475137: On Monday, Roger drove to work in 2 hours. On Tuesday, he averaged 15 miles per hour more, and it took him 30 minutes less to get to work. How far (in miles) does he travel to work?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Begin with

where is the distance to work, is the rate of speed for the 2 hour trip, and is the time.

For the Monday trip:



which is all we can say because we don't know the distance or the rate.

For the Tuesday trip we know the distance is the same and the rate is 15 mph faster and the time is 30 minutes (0.5 hour) shorter, so:



Generally you want to arrange things so that you are solving for the variable that answers the question asked directly. However in this case the arithmetic is much simpler if you solve for the rate and then compute the distance.



Just simplify and solve for . Then compute to get the distance.

John

My calculator said it, I believe it, that settles it
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