Question

An art teacher mixes 5 parts blue paint and 3 parts white paint to make a light blue color to paint a Tar Heels logo on a school mural. If she needs a total of 40 gallons of light blue paint to paint the mural, how many gallons of blue paint will she use?

Answer 1

50

Explanation:

For starters, we make the following assumptions

Let the blue paint be represented by x

Let the white paint be represented by y

Now, forming an inequality equation from the question, we can say that

5x + 3y = 1

And from the second part, we are told that 40 gallons of light blue paints are needed.

If 5x + 3y = 1, then multiplying all by 40, we have

200x + 120y = 40

This means that 200 parts of blue paints is needed to be mixed with 120 parts of white paints to get the desired 40 gallons.

There are 4 parts in a gallon, so 200 parts = 200/4 gallons, = 50 gallons of blue paints