1. Equivalent Ratios Problem Solving
Finding the missing number in a proportion

2. Solving Proportions with missing numbers
Write as fractions
Ask yourself, “What did I multiply or divide by to get from the known term in ratio A to the known term in ratio B?” =
What can you multiply or divide 4 by to get 16?
Do the SAME thing to the top number to find your missing value.
The missing value can be in any position.

3. Find the missing numbers

5. The ratio of boys to girls is 2 to 3
The ratio of boys to girls is 2 to 3. These are 12 boys in the class, how many girls are in the class?

6. The ratio of boys to girls is 4 to 1
The ratio of boys to girls is 4 to 1. There are 30 students in the class. How many girls are in the class?
Some problems will give you a total. If you add to the two terms in the ratio, it will give you a total as well.
1st: Add the two terms in the original ratio = 5
This would be like saying it is a class with just 5 students.
2nd: Set up your proportion.
1 girl/5 students = ? Girls/30 students
3rd: Multiply or divide to find the missing number.

7. The ratio of boys to girls is 4 to 1
The ratio of boys to girls is 4 to 1. There are 20 students in the class. How many boys are in the class?
1st: Add the two terms in the original ratio = 5
5 students in the class
2nd: Set up your proportion.
4 boys/5 students = ? boys/20 students
3rd: Multiply or divide to find the missing number.

8. The ratio of apples to oranges is 5 to 2
The ratio of apples to oranges is 5 to 2. If there are 16 oranges, how many pieces of fruit are in the basket?

9. If there are 24 pints of milk in the cooler
If there are 24 pints of milk in the cooler. How many pints are strawberry?
Type of Milk
Chocolate 1
Regular 4
Strawberry 3

10. If there are 20 pints of regular milk. How many pints are chocolate?
Type of Milk
Chocolate 1
Regular 4
Strawberry 3

11. If there are 2 regular pints of milk. How many total pints are there?
Type of Milk
Chocolate 1
Regular 4
Strawberry 3

12. The picture shows the ratio of pears to strawberries
The picture shows the ratio of pears to strawberries. If there are 30 pieces of fruit, how many pears? …how many strawberries?

13. The picture shows the ratio of the dancers on stage
The picture shows the ratio of the dancers on stage. If there are 30 dancers, how many guys are dressed in yellow?

14. The picture shows the ratio of the dancers on stage
The picture shows the ratio of the dancers on stage. If there are 20 dancers dressed in blue, how many guys are dressed in yellow?

15. The picture shows the ratio of the dancers on stage
The picture shows the ratio of the dancers on stage. If there are 24 dancers dressed in yellow, how many total dancers are there?

16. What is the ratio of cats to dogs?

17. If there are 10 cats, how many dogs are there?

18. If the total number of cats and dogs is 30, how many cats are there?

19. What is the ratio of scoops of ice cream to cherries?

20. If there are 7 cones, how many scoops of ice cream are there?

21. If there are 48 scoops of ice cream how many cherries will you have?

22. You get 20 erasers for $1. 90 How much would 5 erasers cost
You get 20 erasers for $1.90 How much would 5 erasers cost? How much would 15 erasers cost?

23. If Allya can ride his bike to a town that is 21 miles away in 45 minutes how far can he ride in 60 minutes?

24. A car can go 50 miles on 2 gallons of gasoline
A car can go 50 miles on 2 gallons of gasoline. How far can it go on 15 gallons?

25. On the average, Jack makes a basket nine times out of twelve shots when he is practicing. How many baskets can he expect to make when he tries 20 shots?

26. You get 30 pencils for $4.50
How much would 3 pencils cost?
How much would 12 pencils cost?

27. A train travels at a constant speed of 80 miles per hour.
How far will it go in 90 minutes?

28. A train travels at a constant speed of 80 miles per hour.
How long will it take for the train to travel 28 miles?