Question

To make a certain household paint, you need to mix 3/4L of white paint, 15ml of red paint and 10ml of yellow paint. If you need a total volume of 31 litres of this paint, how much of each colour must you mix?

Answer 1

$$\dfrac{3}{4}(1000\ mL)=750\ mL$$ $$750+15+10=775(mL)$$

Divide by 5

$$150\ parts+3\ parts+2\ parts=155\ parts$$

The paint mixture as a ratio is $150:3:2.$

$31\ L$ corresponds to $155\ parts$

$0.2\ L$ corresponds to $1\ part$

You need to mix 30 L of white paint with 0.6 L of red paint and 2 L yellow paint to obtain 31 litres of this paint