Ratios, Rates & Unit Rates

Ratios, Rates & Unit Rates

Poll

A ratio is

• compares 2 quantities measured in different units

• a comparison of 2 quantities

• has a denominator of one

Poll

A rate is

• compares 2 quantities measured in different units

• a comparison of 2 quantities

• has a denominator of one

Poll

A unit rate

• compares 2 quantities measured in different units

• a comparison of 2 quantities

• has a denominator of one

Ratio

• comparison of two quantities

• can be same or different units

• written in 3 ways ~ 2 to 3, 2:3, 2/3

Ratios

The ratio of adults to children is 2 to 5. What does this mean?

For every 2 adults, there are 5 children.

Ratios

• 2 adults, 5 children

• 4 adults, ? children

• ? adults, 50 children

Multiple Choice

Ratio of cats to dogs?

• 5:3

• 3:5

• 1 2/3

Multiple Choice

Ratio of football jerseys to cartoon characters?

• 3 to 2

• 2 : 3

• 2 : 5

Rate

• compares two quantities

• measured in different units....mi/hr, price/pound

Unit Rate

• a rate with a denominator of 1 (unit means 1)

• Ex. Shelby drove 70 miles/1 hr or 70 mph

Open Ended

Devin drove 180 miles in 3 hrs. Why is this an example of a rate but not a unit rate?

Open Ended

How can we change 180 miles/3 hrs to a unit rate?

Multiple Choice

Find the unit rate

$46.25 in 5 hrs

• $231.25

• $9.25

• $0.77

• $46.25

Multiple Choice

Find the unit rate:

$78.75 in 9 hrs

• $78.75

• $708.75

• $1.31

• $8.75

Multiple Choice

Find the unit rate:

308 miles on 11 gallons of gasoline

• 28 mpg

• 0.39 mpg

• 3,388 mpg

• 308 mpg

Using Unit Rates

Brian agrees to watch his neighbors dogs for 7 days. His neighbor provided a 128 oz bag of dog food for Buster and Roxy (the 2 dogs). If Buster eats 20.5 oz in 2 days and Roxy eats 22.5 oz in 3 days, does Brian have enough food to feed the dogs all 7 days? Explain.

Multiple Choice

Food Lion has a 2 pound bag of almonds for $21.98. Aldi has a 3.5 pound bag of almonds for $30.25. Which store is the least expensive per oz for the almonds and by how much?

• Food Lion,$ 2.35 less

• Food Lion, $10.99 less

• Aldi, $2.35 less

• Aldi, $8.64 less