Bring On the Wheel

[mathdad]

How many feet does a wheel with a diameter of x inches travel after y hours?
Note: The answer is not a specific number of feet or inches.

Solution:

C = pi•d

Let d = x

C = pi(x inches)(y hours)

Correct?

 

[mathdad]

Note: It travels y revolutions per hour.

 

[HallsofIvy]

Is "y" a time in hours or a speed in revolutions per hour? Or both?

A wheel of diameter x inches has a circumference of $\displaystyle \pi x$ inches so $\displaystyle \frac{\pi x}{12}$ feet. If it is making y revolutions per hour it will travel $\displaystyle \frac{\pi xy}{12}$ feet per hour so a total of $\displaystyle \frac{\pi xy^2}{12}$ feet in y hours.

 

[mathdad]

Is "y" a time in hours or a speed in revolutions per hour? Or both?

A wheel of diameter x inches has a circumference of $\displaystyle \pi x$ inches so $\displaystyle \frac{\pi x}{12}$ feet. If it is making y revolutions per hour it will travel $\displaystyle \frac{\pi xy}{12}$ feet per hour so a total of $\displaystyle \frac{\pi xy^2}{12}$ feet in y hours.

Algebra.com is notorious for having too many incorrect questions posted. I will need to search the site again.