1. 4.1 D - Unit Rates
Lesson 4-1 D
Mrs. Wilson

2. A rate is a RATIO that compares two things that have DIFFERENT units!
What does rate mean?
A rate is a RATIO that compares two things that have DIFFERENT units!
Ex: Students per Bus OR Miles per Hour
The unit rate is the rate for one unit of a given quantity. Unit rates have a denominator of 1.
The word PER means 1 !!!!

3. Going from rate to Unit rate
150 heartbeats in 2 minutes
Rate:
150 heartbeats
See how there are 2 different units of measure?
2 minutes
just DIVIDE to get the Unit Rate!!!
150 ÷ 2 = 75 heartbeats per minute.
You can also write it as…
75 heartbeats / minute

4. Find the Unit Rate
Amy can read 88 pages in 4 hours. What is the unit rate?
(How many pages can she read per hour?)
88 ÷ 4 = 22
So…
22 pages per hour
or pgs / hr
88 pages
4 hours
1 hr
Notice that hours turns to 1…that is the number you divide by!

5. Not all rates will be even numbers!
It is $30 for 4 t-shirts. What is the unit rate?
30 ÷ 4 = 7.5
You have to add a decimal and a zero!!
How much $ is this?
$30
4 shirts
1 shirt
$7.50 for each shirt!

6. Sometimes you know the unit rate already…
Joe’s car goes 20 miles per gallon of gasoline. How far can it go on
8 gallons of gasoline?
*Per Means 1.
Here’s what it looks like!
x 8
20 miles =
1 gallon
8 gallons
x 8
20 x 8 = Joe’s car can go 160 miles on 8 gallons of gas.

7. Sometimes you know the unit rate already…
It costs $15.50 per student for the trip. If there are 20 students going, how much will the total be?
*Per Means 1.
Here’s what it looks like!
x 20
$15.50 =
1 student
20 students
x 20
15.50 x 20 = So it will cost $310 for 20 students to go.

8. If you need to FIND a UNIT rate, you DIVIDE
It’s easy to remember:
If you need to FIND a UNIT rate, you DIVIDE
If you already KNOW the Unit Rate, you MULTIPLY
If you are ever unsure WHICH number to divide by, find the measure that will become a 1. This measure is what you divide by!!!