Rates and Unit Rates
Objective: Using Unit Rates to determine the best price
Beats/min
Rate
a comparison between two numbers with different units.
eg. mph, words per minute, km/h
If you can say the word per it is a rate
ex.
22words : 2 minutes
360km/3hrs
Unit Rate/ Unit Price
A rate expressed as a fraction with the denominator of 1;
The rate or cost for one item or unit
Knowing the unit price allows us to be smarter shoppers. We
can compare the prices of different goods to pick what we think
the best buy is.
Common Examples:
Rate
Ratio
78:304
50km/30min
Unit Rate
300mL/s
5/1
784cm:36parsecs
300km/h
To make something into a unit rate you can set up a
proportion.
Ex. MCHS has two pop machines. You can buy a 591
mL bottle of pop for $2.00 or you can buy a 355mL can of
pop for $1.25. Which is the better buy?
Bottle = 0.003384
Can = 0.003521
Ex. A different store sells boneless steaks for the following prices:
$4.25 for 250g; $7.95 for 500g; and $29.50 for 2000g. Which of these
packages has the lowest unit price?
0.017
0.0159
0.01475