Writing equations from ratios | Maths | Quizalize & Oak National Academy

Starter quiz

Which of the following is the correct way of writing the ratio 1 to 2?

1 ; 2

1 : 2 ✓

1 - 2

1 , 2

1 . 2
There are 36 cans of drink and bags of sweets in a vending machine. The ratio of cans : bags is 2 : 1. 4 of each are sold. What is the ratio of cans : bags now? (In its simplest form)

'5 : 2' ✓
There are 56 vehicles in a car park. The ratio of cars : vans is 5 : 2. 4 more vans enter the car park. What is the ratio of cars : vans now? (Give your answer in its simplest form)

'2 : 1' ✓
The ratio of adults to children at an athletics club is 8 : 5. 8 adults leave, the ratio is now 4 : 3. How many children are members of the club?

'30 ' ✓
3 bags contain counters in the ratio 6 : 3 : 5. Some counters are taken out of 1 bag and put into the other 2. The ratio of counters is now 6 : 5 : 10. What is the minimum number of counters removed?

'6 ' ✓
The ratio of the number of £1 coins to £2 in Sam’s money box is 3 : 2. Their gran gives them 6 more £1 coins, the ratio is now 2 : 1. How much money was in Sam’s money box originally?

£11

£13

£30

£42 ✓

£48

The 3 in $3a$ is the ______.

number

expression

coefficient ✓

unknown

term
What is the equation of $y$ in terms of $x$ ?

$y=6x$

$y={1\over5}x$

$y=5x$ ✓

$y={1\over6}x$
What is the equation of $y$ in terms of $x$ ?

$y={1\over2}x$

$y=2x$

$y={1\over3}x$ ✓

$y=3x$
Match each ratio of $x$ : $y$ to the correct equation of $y$ in terms of $x$ .

1 : 4

⇔

$y=4x$ ✓

4 : 1

⇔

$y={1\over4}x$ ✓

3 : 2

⇔

$y={2\over3}x$ ✓

2 : 3

⇔

$y=1.5x$ ✓

3 : 5

⇔

$y={5\over3}x$ ✓
The ratio of adults to children at a running club is 7 : 5. Which of the following are correct equations linking adults and children?

$a={5\over7}c$

$c={7\over5}a$

$c={5\over7}a$ ✓

$a={7\over5}c$ ✓
$8x-2y = 3x+5y$ . What is the ratio of $x:y$ ?

'7 : 5' ✓

Loading worksheet ...

Loading presentation ...

Ratios can be written as fractions.
A ratio can be used to write an equation.
This equation is another way of representing how the two quantities are connected.
Either of the quantities can be the subject.

When $x : y$ are in the ratio 1 : 2 pupils write the equation as $x = 2y$

The bar models shown in this lesson can help to support pupils with this.

Ratio - A ratio shows the relative sizes of 2 or more values and allows you to compare a part with another part in a whole.
Coefficient - A numerical coefficient is a constant multiplier of the variables in a term.
Equation - An equation is used to show 2 expressions that are equal to each other.