A paint mixer wants to mix paint that is 30% gloss with paint that is 15% gloss to make 3.75 gallons of paint that is 20% gloss. How many gallons of each paint should the paint mixer mix together?

Question

A) 2 1/4 gallons of 30% gloss and 1 1/2 gallons of 15% gloss

B)1 1 /4 gallons of 30% gloss and 2 1/2 gallons of 15% gloss

C) 1 3/4 gallons of 30% gloss and 2 gallons of 15% gloss

D) 1 1/2 gallons of 30% gloss and 2 1/4 gallons of 15% gloss

Answer 1

eliminate a) as you want more of the gloss that's closest to 20%

answer is either b,c or d)

.3x + .15(3.75-x) = .2(3.75)

.3x -.15x = .2(3.75) - .15(3.75)

.15x = .05(3.75)

x = .05(3.75)/.15 = 5(3.75)/15 = 3.75/3 = 1.25 gallons of 30%

and 3.75-1.25 = 2.5 gallons of 15%

B) is correct

20-15 = 5

30-20 =10

10/5 =2

2.5/1.25 = 2

You want twice as much 15% as 30%

2.5 is twice 1.25

2 1/2 = twice 1 1/4