A dairy farmer wants to mix a 85% protein supplement and a standard 35% protein ration to make 1400 pounds of a high-grade 45% protein ration. How many pounds of each should he use?

Answer 1

.85x + .35(1400-x) = .45(1400) solve for x = pounds of 85%

.85x -.35x = .45(1400) -.35(1400)

.5x = .10(1400)

x = (.10/.5)(1400) = 1/5(1400) = 280 pounds of 85%

1400-x = 1400-280= 1120 pounds of 35%

35 is much closer to 45 than 85, so you know you need much more of 35% than of 85%. 35 is within 10 of 45. 85 is within 40 of 45. That 4 times as close

4 x 280 = 1120. You need 4 times as much of 35%