Question

To make 3 litres of pale purple paint you mix:

1.5 litres red
1.25 litres of blue
0.25 litres of white paint.
a How much red paint is needed to make 8 litres of paint?

Answer 1

We need 4 litres of red paint.

Explanation:

We need to take their respective precentages to compare the 3 litres of paint to 8 litres of paint.

`(1.5)/(3) * 100\% = 50\% \\ (1.25)/(3) * 100\% = 41.67\% \\ (0.25)/(3) * 100\% = 8.33\% \\`

Now, we know that the pale purple paint contains 50% red paint, 41.67% blue paint, and 8.33% white paint.

Now, we will transfer these percentages to the 8 litres of paint:

`50\% \: of \: 8 \: litres = 0.5(8) = 4 \: litres \\ 41.67\% \: of \: 8 \: litres = 0.4167(8) = 3.3336 \: litres \\ 8.33\% \: of \: 8 \: litres = 0.0833(8) = 0.6664 \: litres`