Warm UpDivide. Round answers to the nearest tenth.
1. 2.
3. 4.
23.3 3.5
23.8 23.9
420 18
73 21
380 16
430 18
Vocabulary
Rate
Unit Rate
Unit Price
Estimate
Ratio: 903
Rate: 90 miles3 hours
...as a ratio like this,
A rate is a comparison of two quantities measured in different units.
For example, the phrase “90 miles per 3 hours” can be written...
...or as a rate, like this
Unit rates are rates in which the second quantity is 1.
unit rate: 30 miles,1 hour
or 30 mi/h
The ratio 903
can also be simplified by dividing:
903
= 301
Class Example
Geoff can type 30 words in half a minute. How many words can he type in 1 minute?
Write as a rate.
=
Geoff can type 60 words in one minute.
Multiply to find words per minute.
60 words 1 minute
30 words minute
12
30 words • 2 minute • 212
Partner Practice
Penelope can type 90 words in 2 minutes. How many words can she type in 1 minute?
90 words 2 minutes
Write a rate.
=
Penelope can type 45 words in one minute.
90 words ÷ 2 2 minutes ÷ 2
Divide to find words per minute.
45 words 1 minute
Individual Practice
A piece of gold with a volume of 0.5 cubic meters weighs 9650 kilograms. What is the density of gold?
Gold has a density of 19,300 kg/m3.
9650 kg0.5 m3
Write the rate.
Multiply to find kilograms per 1 m3.
9650 kg • 20.5 m3 • 2
19,300 kg1 m3
To estimate is to find a value that is close to the actual value, but not necessarily the true value.
Estimate the unit rate.
Partner Practice
313 Is not divisible by 8, so choose a number close to 313 that is divisible by 8.
313 feet in 8 seconds
313 feet to 8 seconds is approximately 40 feet per second.
313 feet8 seconds
320 feet8 seconds
40 feet1 second
Divide to find feet per second.
Estimate each unit rate.
Individual Practice
Choose a number close to 583 that is divisible by 85.
583 soccer players to 85 soccer balls.
583 soccer players to 85 soccer balls is approximately 7 players per soccer ball.
583 players85 soccer balls
595 players85 soccer balls
7 players1 soccer ball
Divide to find players per soccer ball.
Unit price is a unit rate used to compare price per item.
Pens can be purchased in a 5-pack for $1.95 or a 15-pack for $6.20. Which pack has the lower unit price?
Class Practice
Set up proportions for both situations.price for package
number of pens =$1.95
5= $0.39
price for packagenumber of pens
= $6.2015
$0.41
The 5-pack for $1.95 has the lower unit price.
Divide the price by the number of pens.
Compare to determine your answer.
Jamie can buy a 15 oz jar of peanut butter for $2.19 or a 20 oz jar for $2.78. Which jar has the lower unit price?
Partner Practice
$2.1915
= $0.15
= $2.7820
$0.14
The 20 oz jar for $2.78 has the lower unit price.
price for jarnumber of ounces
price for jarnumber of ounces
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