1) 5 cups of yellow paint; because if 10 cups of yellow paint are used for 2 cups of blue paint, then you would use 5 cups of yellow paint to even out the pigment of one cup of blue.
2) 3 cups of blue paint, and 15 cups of yellow paint
3) 5 cups of yellow for every cup of blue paint
4) for every cup of blue paint 5 cups of yellow are used to get the same shade of green
You should get photo math you can take a picture and it will give you the answer and show you how to solve it