ShmoopTube

00:02

And we're getting' math-y with it...

00:04

Jennifer hates exercise.

00:05

So, to keep herself motivated, she hung a cookie in front of her treadmill.

00:10

She ran for 12 minutes on the treadmill at a rate of 6.5 miles/hour.

00:14

Then she ran for 10 min at a rate of 5.5 miles/hour.

00:18

What was her average speed during her workout-slash-race for the cookie?

00:22

Round to the nearest hundredth of a mile.

00:24

Here are the potential answers...

00:28

Okay... we need to find Jennifer's average speed.

00:31

Luckily, she's pretty consistent and only changes speeds once...

00:35

Part 1.

00:36

The cookie still had that freshly baked aroma, so no wonder.

00:36

She ran at a rate of 6.5 miles per hour for 12 minutes.

00:39

Let's figure out how many miles motivated Jennifer ran.

00:42

6.5 miles per hour times 1 hour over 60 minutes times 12 minutes equals 1.3 miles.

00:51

Now on to part 2.

00:52

Jennifer slowed down to a rate of 5.5 miles per hour for 10 minutes.

00:56

How many miles did tired Jennifer run? 5.5 miles per hour times 1 hour over 60 minutes

01:02

times 10 minutes equals 0.92 miles.

01:06

Motivated Jennifer plus Tired Jennifer ran

01:09

a total of 2.22 miles in 22 minutes. The average speed is measured in miles per

01:15

hour, so we have to convert 22 minutes to hours.

01:18

22 minutes times 1 hour over 60 minutes is 0.36667 hours.

01:25

2.22 miles divided by 0.36667 hours is equal to 6.05 miles per hour.

01:32

So our answer is E.

Full Transcript