A gallon of green house paint is made by mixing two parts yellow to three parts blue

Question

How many gallons of yellow paint will be needed to make 20 gallons of green paint

Answer 1

2 parts yellow to 3 parts blue

2+3=5

20 gallons needed

20/5=4

4*2=8 gallons yellow

4*3=12 gallons blue

 

yellow     blue

2            3

4            6

6            9

8            12    8+12=20

Answer 2

Let's make the two parts of yellow and three parts of blue into fractions of a whole.

We know we end up with a whole gallon of paint, so the combination of yellow and blue must equal one gallon. So we have two parts plus three parts means 5 parts total, so 2/5 = .4, and 3/5 =.6)

 

Y=.4G

B = .6G

 

G = 20

Y = .4(20) = 8 gallons

B = .6G = 12 gallons