Understanding Ratios
What is a ratio?
A comparison of two quantities using division.
What does it mean for two ratios to be equivalent?
They have the same value when simplified.
What is a rate?
A ratio that compares two quantities with different units.
The ratio of cats to dogs is 2:3. If there are 8 cats, how many dogs are there?
12 dogs.
What does “percent” mean?
Per hundred” or “out of 100.”
Write the ratio of 3 apples to 5 oranges in three ways.
3 to 5, 3:5, or 3/5.
Find an equivalent ratio to 3:4.
6:8, 9:12, etc.
If a runner goes 10 miles in 2 hours, what is the unit rate?
5 miles per hour.
A mix has a ratio of 4 red marbles to 6 blue marbles. How many total marbles are there if there are 10 blue?
15 Marbles
25% of 80 is what number?
20
25/100 = x/80 You cross multiply.
In a class, there are 12 boys and 16 girls. What is the ratio of boys to total students?
12:28 or 3:7.
Which ratio is equivalent to 5:10 ?
Is it 1:2 or 2:3?
1:2.
A car travels 240 miles on 8 gallons of gas. Find the unit rate.
30 miles per gallon.
The ratio of boys to girls is 5:8. If there are 65 students total, how many are boys?
25 boys.
Write 0.4 as a percent
40%
What does the ratio 4:1 mean in words?
For every 4 of one quantity, there is 1 of the other.
Simplify the ratio 12:18.
2:3.
You buy 3 notebooks for $6. What is the cost per notebook?
$2 per notebook.
You have a bag with a 3:2 ratio of red to green candies. If there are 21 red candies, how many green are there?
14 Green Candies
What is 30% of 250?
75.
A recipe uses 2 cups of sugar for every 5 cups of flour. What is the ratio of sugar to flour?
2:5
A car travels 60 miles in 2 hours. How far will it travel in 5 hours at the same rate?
150 miles (use equivalent ratios 60/2 = x/5).
If 15 pencils cost $4.50, what is the cost per pencil?
$0.30 per pencil.
A model uses unit rate of 1:50. If a building is 8 feet tall on the model, how tall is the real building?
400 feet tall.
A shirt costs $40 and is on sale for 25% off. What is the sale price?
25% of 40 is $30.
25/100 = x/40
x=10
40-10= $30