Soybean meal is 16% protein, cornmeal is 8% protein. How many pounds of each should be mixed together in order to get 320-lb mixture that is 13% protein

Question

For a question that is kinda tricky to me and i need lots of help with it 

Answer 1

S + C = 320 --> C = 320 -S

 

0.16S + 0.08C = 0.13*320 = 41.6

 

16S + 8C = 4160

 

16S + 8(320 - S) = 4160

 

16S + 2560 - 8S = 4160

 

8S + 2560 = 4160

 

8S = 4160 -2560

 

8S = 1600

 

S = 1600/8 = 200

 

200 pounds of Soybean and 120 pounds of cornmeal