Joe is painting his ceiling and needs to mix red and blue paint. In order to maintain the correct colour he must keep the amount of blue and red paint in direct proportion. For example, when his mixture contains 10 L of red paint, it contains 20 L of blue paint.

Write an equation relating the amount of blue paint in litres (b) and the amount of red paint in litres (r).

Drag the solution steps into the correct order.
Check your answer with the solution.

Use the equation to find:

1. the number of litres of blue paint that Joe would need to add to 5 L of red paint to create the correct colour.

2. the number of litres of red paint that Joe would need to add to 15 L of blue paint to create the correct colour.