### Home > INT2 > Chapter 9 > Lesson 9.3.4 > Problem9-123

9-123.

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?

1. $140\pi \; \text{in}$

1. $8400\pi \; \text{in}$

1. $3360\pi \; \text{in}$

1. $16800\pi \; \text{in}$

Circumference $= 2$ * $π$ * diameter 'revolution'.
In this case, our diameter is $14$ inches.
We also know we have $120$ revolutions per minute, with $5$ minutes given.

By using dimensional analysis, we see that the circumference multiplied by the
total revolutions gives us $16800π$ inches. The answer is D.