Question 1008995
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A truck with 48-in.-diameter wheels is traveling at 45 mi/h.
How many revolutions per minute do the wheels make? 
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1 mile = 63360 inches (see this <A HREF=https://www.google.com/#q=converter+miles+inches>article</A> in Wikipedia).


The truck covers {{{45/60}}} = {{{3/4}}} miles per minute.

It is {{{3/4}}}.{{{63360}}} = 47520 inches per minute.


The circumference of the wheel is {{{2*pi*(48/2)}}} = 2*3.14*24 = 150.72 inches.


Hence, the number of revolution of the wheel is {{{47520/150.72}}} = 315.28 per minute.