A dairy farmer wants to mix a 50% protein supplement and a standard 25% protein ration to make 1400 pounds of a high-grade 30% protein ration. How many pounds of each should he use?

Question

how many pounds for 50%

how many pounds for 25%

Answer 1

a + b = 1400 -----> a = 1400 - b

0.5a + 0.25b = 0.3(1400)

Substitute!

0.5(1400 - b) + 0.25b = 0.3(1400)

700 - 0.5b + 0.25b = 420

-0.25b = -280

b = 1120 lbs

a = 1400 - 1120

a = 280 lbs