To make a certain shade of orange calvin uses a rate of 2 ounces of yellow paint to 5 ounces of red paint if he uses 200 ounces of red paint how many ounces of yellow paint

80 ounces of yellow paint

Working:
As we know 2 ounces of yellow paint to 5 ounces of red paint, we can make a ratio:

2:5

Then we look at the question which says 200 ounces of red paint, so we replace the 5 ounces of red paint in the ratio with 200.

2:200

Then we figure out how much the 5 has been multiplied by to get to 200. We do this by doing

200 divide 5 = 40

Therefore we times the 2 ounces of yellow paint by 40 which gets us:

80:200

We can think of it as a fraction too to confirm our

Simplify 80 / 200

We get 2 / 5.

If you need me to further explain something please just ask :)