# Write a Ratio from Amounts

In this worksheet, students practise writing ratios from a given amount.

Key stage:  KS 4

GCSE Subjects:   Maths

GCSE Boards:   AQA, Eduqas, Pearson Edexcel, OCR

Curriculum topic:   Ratio, Proportion and Rates of Change

Curriculum subtopic:   Ratio, Proportion and Rates of Change, Calculations with Ratio

Difficulty level:

### QUESTION 1 of 10

What is a ratio?

A ratio is simply a way of comparing two or more quantities.

What does a ratio look like?

A ratio is just two numbers written with a colon between them. For example 3:5  2:7 etc

Does the order matter?

Yes, absolutely. 3:1 is not the same as 1:3

Example 1: I have 4 red balls and 6 blue balls. Write a ratio for the amount of red balls to blue balls.

We have to look at the question here, it asks for red to blue balls. This can be written as 4 : 6.

While this can be cancelled down, don't worry about that at this point, we will focus on that in another lesson.

I have 3 red balls and 6 blue balls. Write a ratio of red balls to blue balls.

(Don't put any spaces in your answer, the system will mark it wrong)

I have 4 red balls and 5 blue balls. Which of these ratios could be correct?

4:5

5:4

Both

In a class, there are twice as many boys as girls. Write the ratio of boys to girls.

In a class, there are twice as many boys as girls. Write the ratio of girls to boys.

I have 7 dark chocolates and 10 llight ones. Which of these is the correct ratio for dark : white chocolates?

7:10

10:7

Both are correct

A ratio is used to...

7:10

10:7

Both are correct

Match the situation to the ratio.

## Column B

10 boys and 15 girls. Boys : Girls
10:15
10 boys and 15 girls. Girls to Boys
15:10
3 red balls and 5 green balls. Green to red
5:3
3 veggie pies and 5 meat pies. Veggie to Meat
3:5

A car does 42 mpg and a motorbike does 63 mog.

Write a ratio to compare the mpg for the bike and the car

I have 6 oranges and 9 apples. Is the ratio of oranges to apples...

6:9

9:6

One side of a rectangle is three times the length of the other.

Write a ratio to compare the sides of the rectangle.

• Question 1

I have 3 red balls and 6 blue balls. Write a ratio of red balls to blue balls.

(Don't put any spaces in your answer, the system will mark it wrong)

3:6
1:2
EDDIE SAYS
Remember to keep it in the same order. Red: Blue 3: 6
• Question 2

I have 4 red balls and 5 blue balls. Which of these ratios could be correct?

Both
EDDIE SAYS
It could be both. The question doesn't specify the order so both are valid answers.
• Question 3

In a class, there are twice as many boys as girls. Write the ratio of boys to girls.

2:1
EDDIE SAYS
If we are told there are twice as many boys. This means there are 2 boys to every one girl. As we are asked for the ratio boys:girls This gives a ratio of 2:1
• Question 4

In a class, there are twice as many boys as girls. Write the ratio of girls to boys.

1:2
EDDIE SAYS
If we are told there are twice as many boys. This means there are 2 boys to every one girl. As we are asked for the ratio girls: boys This gives a ratio of 1:2
• Question 5

I have 7 dark chocolates and 10 llight ones. Which of these is the correct ratio for dark : white chocolates?

7:10
EDDIE SAYS
This one does specify an order. It asks for Dark : Light so the dark ones must come first.
• Question 6

A ratio is used to...

EDDIE SAYS
A little call back to the intro. Ratios are used to compare quantities
• Question 7

Match the situation to the ratio.

## Column B

10 boys and 15 girls. Boys : Girl...
10:15
10 boys and 15 girls. Girls to Bo...
15:10
3 red balls and 5 green balls. Gr...
5:3
3 veggie pies and 5 meat pies. Ve...
3:5
EDDIE SAYS
It\'s all about the order you are asked for. If it asks for boys first, the first number has to represent the boys.
• Question 8

A car does 42 mpg and a motorbike does 63 mog.

Write a ratio to compare the mpg for the bike and the car

63:42
21:14
9:6
3:2
EDDIE SAYS
Did you notice I switched the order? The bike had to come first. 63:42
• Question 9

I have 6 oranges and 9 apples. Is the ratio of oranges to apples...

6:9
EDDIE SAYS
Did you put oranges first? Well done. If not, remember to look at the order in the question.
• Question 10

One side of a rectangle is three times the length of the other.

Write a ratio to compare the sides of the rectangle.

1:3
3:1
EDDIE SAYS
Three times means the sides are in the ratio 1:3 As the question doesn't ask for a specific order, it could also be 3:1
---- OR ----

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