Ratios
Name two equivalent ratios
For 3:7
6: 14
12:28
9:21
21:49
What is the constant speed formula
Distance Divided by Time
What is the formula for unit rate
For every 4 boys in a class, there are 8 girls. If there are 20 girls, how many boys are there?
Answer: 4:8 = 1:2 → 20 ÷ 2 = 10 boys
On a table the rules are
- Whatever I do to one side I must do to the other
There are 8 boys and 12 girls in a class. What is the ratio of boys to girls?
8:12 → simplifies to 2:3
A car travels 60 miles in 2 hours. What is its constant speed?
A car travels 60 miles in 2 hours. What is its constant speed?
On a double number line, 2 apples cost $4. How much do 5 apples cost if the ratio stays the same?
$4 ÷ 2 = $2 per apple → 5 × 2 = $10
A fruit stand sells 3 apples for every 6 oranges. If the pattern continues, how many oranges would there be when there are 9 apples?
Multiply by 3 → 6 × 3 = 18 oranges
Fill in the missing value on the double number line:
Miles → 2 4 6 __ 10
Hours → 1 2 3 __ 5
missing values are 8 miles and 4 hours
A recipe calls for 4 cups of flour and 2 cups of sugar. What is the ratio of flour to sugar?
4:2 → simplifies to 2:1
A train travels 90 miles in 3 hours. What is its constant speed?
90 ÷ 3 = 30 miles per hour
A double number line shows that 3 notebooks cost $6. How much would 7 notebooks cost?
$6 ÷ 3 = $2 each → 7 × 2 = $14
A juice recipe uses 2 cups of juice for every 4 cups of water. How many cups of water are needed for 5 cups of juice?
2:4 = 1:2 → 5 × 2 = 10 cups of water
Jada earns $50 for 4 hours of babysitting. How much will she earn if she works 6 hours at the same rate?
$50 ÷ 4 = $12.50 per hour → 6 × 12.5 = $75
There are 15 red marbles, 10 blue marbles, and 5 green marbles in a bag. What is the ratio of red to total marbles?
15:30 → simplifies to 1:2
A runner jogs 12 miles in 1.5 hours. What is the runner’s constant speed?
12 ÷ 1.5 = 8 miles per hour
On a double number line, 4 cups of juice require 2 scoops of mix. How many scoops are needed for 10 cups?
2 ÷ 4 = 0.5 scoops per cup → 10 × 0.5 = 5 scoops
Each student gets 3 pencils. If 5 students need 15 pencils, how many pencils would 10 students need?
5:15 = 1:3 → 10 × 3 = 30 pencils
Each student receives 3 notebooks. If 3 students need 9 notebooks, how many notebooks are needed for 5 students?
9 ÷ 3 = 3 per student → 5 × 3 = 15 notebooks
A school has 120 students and 8 teachers. What is the ratio of students to teachers?
120:8 → simplifies to 15:1
A bike travels at a constant speed of 15 miles per hour. How far will it travel in 4 hours?
15 × 4 = 60 miles
A car travels 60 miles in 2 hours. Use a double number line to find how far it travels in 5 hours.
60 ÷ 2 = 30 miles per hour → 5 × 30 = 150 miles
A painter mixes paint in a ratio of 4 parts blue to 6 parts red. How much blue paint should be mixed with 9 parts of red paint to keep the same color?
6 → 9 (×1.5) → 4 × 1.5 = 6 parts blue paint
A recipe uses 3 cups of flour for every 2 cups of sugar. If you have 12 cups of flour, how many cups of sugar will you need to keep the same ratio?
3:2 → multiply by 4 → 2 × 4 = 8 cups of sugar