Question

Soybean meal is 16% protein. How many pounds of each should be mixed together to get 320 lb mixture that is 15% protein?

How many lbs of cornmeal?

How many lbs of soybean?

Answer 1

What percent of cornmeal is protein?

Answer 2

Cornmeal is 8 %

Answer 3

Try setting up a table:

Lbs Percent Protein
Soybean: S 16 16*S
Corn: C 8 8*C
--------------------------
Total: 32 15 32*15
where 1st and 3rd columns should add up to total

S+C = 32
16S +8C = 32*15

Answer 4

sorry, 320 not 32

Answer 5

Then use elimination or substitution to solve for S and C

Answer 6

S+C = 320
16S +8C = 4800

Multiply top equation by -8, to eliminate variable C
-8S -8C = -2560
16S+8C = 4800
----------------
8S = 2240
S = 280

Substitute it back in to solve for C