math
posted by jason on .
soybean meal is 18% protein; cornmeal is 9% protein. how many pounds of each should be mixed together in order to get 360lb mixture that is 14%
How many pounds of cornmeal should be in the mixture? 200
how many lbs of soybean meal should be in the mixture? 160
can someone tell me if I have this right?

let x = pounds of soybean meal
let y = pounds of cornmeal
There should be a total of 360 pounds. Therefore, x+y = 360
The protein % is .14. Out of 360 pounds, that would be 360*.14 = 50.4
Therefore, .18x + .09y = 50.4
substitution:
x=360y
.18(360y) + .09y = 50.4
64.8  .18y + .09y = 50.4
.09y = 14.4
y = 160
x+y = 360
x+160 = 360
x = 200
200 pounds of soybean meal
160 pounds of cornmeal
Checking my work:
.18x + .09y = 50.4
.18*200 + .09*160 = 50.4
50.4 = 50.4