Unit Rate

Lesson Objective:

Students will be able to calculate and compare unit rates.

Student-Facing Learning Target:

I can calculate unit rates and use unit rate to compare.

Vocabulary:

1.) [b]Unit Rate: [/b]the ratio of two different units with the denominator being 1.

Do Now:

1.) Create a word problems for the following ratio:[br] [u]9.50[br][/u] 1

2.) Simplify the expression:[br][br] [math]\frac{4+3\left(2.6-4\right)}{2}[/math]

Part One: Unit Rate

When we are looking at unit rates, we are looking for a unit per 1. [br][br]When writing the unit rate, you need to write it similar to a proportion but making sure which ever item is in the denominator is the item that can be found per 1. [br][br]Example:[br][br]3 ounces of chocolate costs $1.75. Find the cost for 1 ounce of chocolate.[br][math]\frac{2.75}{3}=\frac{x}{1}[/math][br][br][i]You need to look at what we did to 3 to get to 1 in the denominator, in this case we divided by 3. Similar to fractions and ratios, what we do the denominator, we must do to the numerator.[br][/i][br][math]\frac{2.75}{3}=\frac{0.92}{1}[/math] [br]It costs $0.92 per ounce of chocolate.[br]

A.) 10-ounce box of cereal cost $2.79. Find the cost for 1 ounce of the cereal.

B.) 13 ounce box of cereal costs $3.99. Find the cost for 1 ounce of cereal.

C.) In order to get the best deal which item will you buy?

Example 1:

Mr. Polonia needs to purchase 60 AA batteries. A nearby store sells a 20-pack of AA batteries for $12.49 and a 12-pack of the same batteries for $7.20.

a.) Use unit rate to explain which choice is a better bargain.

b.) What is the difference between the costs of one battery?

Example 2:

Chris Johnson ran the 40-yard dash in 4.24 seconds. What is the rate of speed?

Example 3:

Who walks at a faster rate: someone who walks 60 feet in 10 seconds or someone who walks 42 feet in 6 seconds?

Example 4:

Practice Problems:

Find each unit rate.

1.) Type 800 words in 12 minutes is how many words per minute?

2.) 192 students in 4 buses is how many students in each bus?

3.) 357 miles in 5 hours is how many miles per hour?

4.) 8 ducks cost $23.60, how much does It cost per duck?

5.) 7 penguins for $188.88, how much does it cost per penguin?