Warm-upWednesday, October 21,

2009

Solvea)Find the unit rate of a 12-oz bottle of orange juice that sells for $1.29

b) If you are driving 65 miles/hour, how many feet per second are you driving?

Quick Check2. Suppose you walk 2 miles in 35 minutes

a) Find the average walking speed. Write a rule to describe the distance d you walk as a function of the time t you walk.

b) Use the function to find how far you would walk in an hour.

Quick Check3. A sloth travels

0.15 miles per hour. Convert this speed to feet per minute.

4. Solve each proportion

a. 1014

2 xx

Quick Checkb. c.

7

35

4

15

y

y

4

5

6

3

ww

Rates and Conversions

Section 6.1Objective: We will be able to express rates with different

units.

Changing Units

Change 27 feet per second to inches per second.

Start by writing the rate as a division sec1

ft27

Next change units as needed to finish the multiplication and get the correct units

ft1

in12ft1

ft1

Second we multiply by fancy “ones”. This might change the look of the problem, but not its value.

sec1

in324

Finally, we multiply to get our answer.

Another Example(not animated)A pool fills at 12 quarts per minute.

Find out how many gallons per hour the pool fills.

Before You Try!Please copy down (and use!!!)

these helpful English conversions:1 mile = 5280 feet1 cup = 8 fluid ounces1 pint = 2 cups1 quart = 2 pints1 gallon = 4 quarts1 pound = 16 ounces

Now You Try!Change $7.10 per hour to dollars

per minute.

Change 65 miles per hour to feet per second.

Try some more!Convert 52 inches per minute to

yards per hour.

Change 36 miles per year to inches per hour.

Some thoughts about why.Why would we possibly bother with this?

At the 2008 Olympics Usain Bolt ran the 100 meter dash in 9.69 sec. How fast is that?

(We change rates to gain meaning)

If one job pays a yearly salary of $45,000 and another pays $20 an hour, which pays more assuming 40-hour work weeks?

(We change rates to solve problems)

Homework Time!With lots of time to work on it, here

is your homework!!!

Page 185 – 186: 1 – 37 odd

Ticket to Leave1. Bonnie and Tim do some yard work for

their neighbor. The ratio comparing the amount of time each one works is 7:4. The neighbor pays them $88. If Bonnie worked more, how much should each of them receive?

2. If 2 tons of rock costs $15.50, then how many tons of rock can you buy for $45?