



 
Hi Edward, If the tire has a diameter of 28.2 inches then its circumference is $\pi \times 28.2 = 88.59 \mbox{ inches.}$ Thus the tire travels at a rate of 88.59 inches per revolution. There are 60 minutes in an hour so 8 miles per hour is $\frac{8}{60} = \frac{2}{15} \mbox{ miles per minute.}$ There are 5280 feet in a mile and 12 inches in a foot so \[\frac{2}{15} \mbox{ miles per minute } = \frac{2}{15} \times 5280 \times 4 = 848 \mbox{ inches per minute.}\] One revolution is 88.59 inches so at 8 miles per hour the wheel is rotating at $\frac{8448}{88.59} = 95.3 \mbox{ revolutions per minute.}$ Penny  


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