Question 475137
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Begin with *[tex \Large d\ =\ rt]


where *[tex \Large d] is the distance to work, *[tex \Large r] is the rate of speed for the 2 hour trip, and *[tex \Large t] is the time.


For the Monday trip:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d\ =\ 2r]


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:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d\ =\ 1.5(r\ +\ 15)]


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.


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 2r\ =\ 1.5(r\ +\ 15)]


Just simplify and solve for *[tex \Large r].  Then compute *[tex \Large 2r] to get the distance.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
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