CPM Homework Help : CCG Problem 10-24

Multiple Choice: Jill’s car tires are spinning at a rate of $120$ revolutions per minute. If her car tires’ radii are each $14$ inches, how far does she travel in $5$ minutes?

$140π\text{ in.}$

$8400π\text{ in.}$

$3360π\text{ in.}$

$16800π\text{ in.}$

Step:

$2πr = 2π(14) = 28π$

So, in one revolution the tire travels $28π$ inches.

Answer:

$\frac{28\pi\ \text{inches}}{1\ \text{revolution}}\cdot\frac{120\ \text{revolution}}{1\ \text{minute}}\cdot\frac{5\ \text{minutes}}{1\ \text{trip}}\cdot\frac{16800\pi\ \text{inches}}{1\ \text{trip}}$

(d) $1680π\text{ in.}$