How many lbs or each should be in the mixture?

Question

Soybean meal is 14% protein ; cornmeal is 7% protein. How many pounds of each should be mixed together in order to get 280 -lb mixture that is 13 % protein?

Answer 1

Imagine 2 pots, one containing x lbs of 14% protein soybean meal, and the other containing 280-x lbs of 7% protein corn meal.

 

The protein value, combined, is 0.14x + 0.07(280-x) and this equals 0.13(280).

 

so you just solve the equation  0.14x + 0.07(280-x)  = 0.13(280).

 

I recommend multiplying all terms by 100 to rid yourself of decimals.

Answer 2

X is the amount of soybean meal

Y is the amount of corn bean meal

X+Y = 280

0.14X + 0.07Y = 0.13x280

solve the system by multiplying the first equation by 0.14

0.14X+.14Y =39.2

substruct the second from the first

 

.07Y =2.8

Y =40 lb

X = 240lb