Answer:
You didn't provide answer options. The correct answer option will be the one where the ratio of red paint to yellow paint is 3:8.
Step-by-step explanation:
To make orange, you need some amount of red and some amount of yellow. As long as you mix them in the same proportions, you will get the same orange colour, regardless of how much total paint you're using. It's the RATIO between colours that matter, not how much colour is used.
In this case we are told that to make orange you can use any of the following combinations:
10.5mL red / 28mL yellow
9mL red / 24mL yellow
7.5mL red / 20mL yellow
Just take any of these and convert into a fraction. The middle option is easiest because it uses whole numbers:
This means for every 3 units of red, you need 8 units of yellow. Whichever answer option has red and yellow in that ratio is the correct answer.