Question 622515
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Distance equals rate times time, so *[tex \LARGE d\ =\ 2(r\ +\ 5)] and *[tex \LARGE d\ =\ 7(r\ -\ 5)].  But *[tex \LARGE d\ =\ d] so:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 7(r\ -\ 5)\ =\ 2(r\ +\ 5)]


Solve for *[tex \LARGE r]


By the way, tell your teacher that if s/he is going to make up problems, construct them so that the answers make sense in the real world.  Alvin's sustained paddling speed approximates the speed of the world canoe record holder for a 5000 meter race and is only slightly slower than the record for the kayak at the same distance.  The distance here is NINE times as far.  No human can paddle that fast for that far.


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