Ahouse painter has 1 gallon of paint that is 35% yellow and another gallon that is 60% yellow. the painter needs a gallon of paint that is 45% yellow. how much of each color should the painter use?

Let be the volume of the 35% yellow paint the painter will use, and the volume of the 60% yellow paint.

The painter wants to end up with 1 gal of paint, so

Each gallon of 35% yellow paint contributes 0.35 gal of yellow paint, while each gallon of 60% yellow paint contributes 0.60 gal of yellow paint. The painter wants to end up with a 45% mixture, so that

Solve the system and you get

the correct answer is c