Year 8: Split a total based on a ratio

This cheat sheet helps you split a total amount into parts based on a given ratio.

What is a ratio?

A ratio compares two amounts. For example, a ratio of 2:3 means that for every 2 parts of the first amount, there are 3 parts of the second amount.

How to split a total

1. Understand the ratio: Make sure you understand what each number in the ratio represents.
2. Total parts: Add up all the numbers in the ratio. This tells you how many parts the total is divided into.
3. Calculate one part: Divide the total amount by the total number of parts. This gives you the value of one part.
4. Multiply to find each part: Multiply the value of one part by each number in the ratio to find the value of each part.

Example

A group needs to buy equipment costing $600. The ratio of the cost of the cameras to the cost of the microphones is 3:2.

1. Total parts: 3 + 2 = 5 parts
2. Value of one part: $600 / 5 = $120 per part
3. Cost of cameras: 3 * $120 = $360
4. Cost of microphones: 2 * $120 = $240

Check your answer: $360 + $240 = $600