CPM Homework Help : CC1 Problem 9-13

Dawn drove $420$ miles in $6$ hours on a rural interstate highway. If she maintains the same speed, how far can she go in $7.5$ hours?

Step 1:

First, find the number of miles Dawn drive in 1 hour (the unit rate, or speed).

$\frac{420\ \text{miles}}{6\ \text{hours}}=70\ \text{miles\ per\ hour}$

Step 2:

Now, multiply the speed (miles driven in one hour) by the number of hours.

$\left ( 70\frac{\text{miles}}{\text{hour}} \right )(7.5\ \text{hours}) = 525 \text{ miles}$

Answer:

If Dawn maintains her speed, she will drive $525$ miles in $7.5$ hours.