Applying systems

Question

A paint mixer wants to mix paint that is 15% gloss with paint that is 30% gloss to make 5 gallons of paint that is 20% gloss. How many gallons of each paint should paint mixer mix together?     

 

 

A. The paint mixer should use 1 2/3 gallons of 15% gallons and 3 1/3 gallons of 3 gloss paint.

 

B. The paint mixer should use 3 gallons of 15% gloss paint and 2 gallons of 30% gloss paint.

 

C. The paint mixer should use 2 gallons of 15% gloss paint and 3 gallons of 30% gloss paint.

 

D. The paint mixer should use 3 1/3 gallons of 15% gloss paint and 1 2/3 gallons of 3 gloss paint.

Answer 1

Sabrina, to find which fits, plug them in. Since 20% is closer to 15% than 30%, we know that more 15% is used than 30%.

 

3(.15) + 2(.3) = 5(.2)

.45 + .6 = 1

Nope

 

(10/3)(.15) + (5/3)(.3) = 5(.2)

.5 + .5 = 1

Sure enough

 

Your answer is D.