Answer:
8 cup of blue
12 cup of red
Explanation:
The first thing is to calculate how much black paint is produced, assuming that the volumes add up, we have to:
1/2 + 1/3 = 5/6
5/6 cup of paint is produced, I want to know how much I need to produce 20 cups, I divide the value I want by the ideal value, that is, 5/6 and thus I obtain the factor that I require:
20 / (5/6) = 24
Now I multiply by 24 each quantity of blue and red paint
1/2 * 24 = 12
1/3 * 24 = 8
Which means you need 12 cups of red paint and 8 cups of blue paint