Rates

Rates

Pre-AP

What is a rate?

• In mathematics, a rate is the ratio between two related quantities in different units. If the denominator of the ratio is expressed as a single unit of one of these quantities, and if it is assumed that this quantity can be changed systematically (i.e., is an independent variable), then the numerator of the ratio expresses the corresponding rate of change in the other (dependent) variable

• Or simply a ratio between two related quantities in different units.

Order still matters!

• Also make sure to pay attention to the information given and the information that is being asked for in the question.

• Oftentimes a question will have an abundance of information and the question will ask about a summative or small part of the total information.

• This would include receipts amongst many examples

Poll

What is a rate

• A comparison of two different quantities of the same unit.

• A fraction that includes decimals

• A ratio of two quantities of different units.

• An expression

Multiple Choice

A receipt from a grocery store visit is shown below:

$7.90 for 3 pounds of chicken

$12.33 for 5.5 liters of milk

$14.80 for 4.8 pounds of almonds

$8.75 for 4 pounds of gummy worms

What is the rate of dollars to pounds of almonds?

• $7.90 : 3 pounds

• 4.8 pounds : $14.80

• $14.80 : 4.8 pounds

• $8.75 : 4 pounds

Multiple Choice

A mechanic hands over your bill for the work he had just completed. Here's the bill:

Tire Rotation: $16.29

Oil Change: $31.95

New Oil: $50.88

New windshield wipers: $20.30

Labor for 1.75 hours: $150.60

What is the rate of cost of labor to hours of labor?

• 1.75 hours : $150.60

• $20.30 : 1.75 hours

• $31.95 : 1.75 hours

• $150.60 : 1.75 hours