Doug and Emily are driving cars on a track, and they both do 20 laps around a 1-mile track. Doug drives an average of 60 miles per hour around the track while Emily drives at an average of 80 miles per hour. When Emily finished her 20 laps how many laps does Doug have left?

When Emily finishes 20 laps Doug has to finish 5 laps.  

Step-by-step explanation:

To find how many laps does Doug have left, we need to calculate the time that Emily takes to finish 20 laps:

Where:

x: is the distance = 1 mile

t: is the time

v: is the speed of Emily = 80 mi/h

The time that takes Emily to do 20 laps is:

Now, we can find the number of laps:                                      

Therefore, when Emily finishes 20 laps Doug has to finish 5 laps.  

I hope it helps you!                    

c.

step-by-step explanation: