Mary mixes white paint and blue paint in the ratio 2:3

She makes a total of 20 litres of paint.

How much more blue paint does she need to add to the mixture so that the ratio of white paint to blue paint becomes 1:7?

44L

Step-by-step explanation:

Mary has 20 liters of paint that have white:blue ratio of 2:3. She wants to make a new mix by adding more blue paint until the ratio becomes 1:7. That means the volume of white paint of the old mid and new mix should be the same.

The volume for the second mix will be:

old mix white paint = new mix white paint

2 / (3+2) * 20L = 1 / (1+7) * V2

2/5 * 20L = 1/8 V2

8L = 1/8 V2

V2 = 8L * 8

V2 = 64L

If the new mix volume is 64L and old mix volume is 20L, then the blue paint needed to be added will be: 64L - 20L = 44L