Proportion is used to scale quantities up or down by the same ratio. This is shown in the following example – what happens if you want to adapt a favourite recipe to serve more people?
Example: Using proportion for more portions …
Frank is a support worker in a residential children’s home. He is making a cake with a group of children to celebrate one of their birthdays.
Here is a recipe for making a sponge cake for four people:
4 oz self-raising flour
4 oz caster sugar
4 oz butter
They need to adapt the recipe so that there is enough for eight people.
How much of each ingredient is needed to make a cake for eight people?
To make a cake for eight people you need twice the amount of each ingredient:
8 oz self-raising flour (4 × 2)
8 oz caster sugar (4 × 2)
8 oz butter (4 × 2)
4 eggs (2 × 2)
Use the example above to help you with the following activity. Remember to check your answers once you have completed the questions.
Activity 19: Scaling up recipes
- This recipe makes ten healthy breakfast bars:
- 220 g oats
- 150 g mixed dried fruit
- 100 g brown sugar
- 2 apples
How much of each ingredient is needed to make 20 breakfast bars?
- This recipe makes four servings of strawberry fruit smoothie:
- 800 ml milk
- 200 g strawberries
- 4 scoops of natural yoghurt
How much of each ingredient is needed for two people?
- This recipe makes a meal replacement drink for two people:
- 300 ml milk
- 60 g powder
How much of each ingredient is needed to serve six people?
- To make 20 breakfast bars you need twice as much of each ingredient:
- 440 g oats (220 × 2)
- 300 g mixed dried fruit (150 × 2)
- 200 g brown sugar (100 × 2)
- 4 apples (2 × 2)
- To make fruit smoothies for two people you need half as much of each ingredient:
- 400 ml milk (800 ÷ 2)
- 100 g strawberries (200 ÷ 2)
- 2 scoops of natural yogurt (4 ÷ 2)
- To make a meal replacement drink for six people you need three times the amount of each ingredient:
- 900 ml milk (300 × 3)
- 180 g powder (60 × 3)
Once you have checked your answers and have got them all correct, please have a go at the next activity.
Activity 20: Looking at ratio and proportion
Note: Calculators not allowed.
A day centre for respite care must have 1 staff member on duty for every 9 service users.
How many staff members are needed to care for 90 service users?
Here is a recipe for a low-fat risotto for two people:
- 200 g mushrooms
- 175 g rice
- 180 ml water
- 180 ml evaporated milk
- Salt and pepper
How much of each ingredient is needed if you want to cook enough risotto for six people?
A ratio of 1:9 means one staff member can look after 9 service users.
To care for 90 service users:
- 90 ÷ 9 = 10
So 10 staff members are required to care for 90 service users.
- To make enough risotto for six people you need three times as much of each ingredient:
- 600 g of mushrooms (200 × 3)
- 525 g of mushrooms (175 × 3)
- 540 ml of water (180 × 3)
- 540 ml of evaporated milk (180 × 3)
In this section you have learned how to use proportion to solve simple problems in everyday life, for example when adapting recipes.