A butcher has some hamburger that is 20% fat and some that is 17% fat. How many pounds of each should be mixed to make 90lb of hamburger that is 18% fat?

Answer 1

Let x = amount of hamburger that is 20% fat

Then, 90 - x = amount of hamburger that is 17% fat

0.20x + 0.17(90 - x) = 0.18(90)

0.20x + 15.3 - 0.17x = 16.2

0.03x = 0.9

x = 30 lb

Use 30 lb of 20% fat hamburger and 60 lb of 17% fat hamburger to make 90 lb of 18% fat hamburger.