Question

Algebra 2 Word Problem: Set up using 2 variables & 2 equations:
"Soybean meal is 16% protein and corn meal is 9% protein. How many pounds of each should be mixed together to get a 350-lb mixture that is 12% protein?"

Answer 1

How many pounds of protein are there in that 350 pound mix?

Answer 2

It doesn't state. That is the entire information. Now I need to set up 2 equations using 2 variables for the missing information.

Answer 3

If the 350 pound mixture is 12% protein, then the number of pounds of protein is 12% of 350.
Make sense?

Answer 4

Using that same reasoning, let S = pounds of soybean meal, and let C = pounds of corn meal; the pounds of protein in the soybean mix is 16% of S and the pounds of protein in the cornmeal mix is 9% of C.

See where I'm going with this? @rosimary

Answer 5

I'm a bit confused. I am suppose to set up 2 equations and then solve by either addition/elimination or substitution method. I am trying to figure out how to write the equations.

Answer 6

Right, I'm trying to show you how you can both equations in terms of pounds of stuff.

Answer 7

The first equation is easy, that's the total weight of the mixture.
pounds of soybeans + pounds of cornmeal = 350 pounds, yes?

Answer 8

yes

Answer 9

so ... s+c=350

Answer 10

Right, what I was saying before was to convert the percentages of stuff into pounds of stuff.

Answer 11

It's important to know what "Soybean meal is 16% protein" means.
It's a proportion:
pounds of protein : pounds of soybeans :: 16 : 100.
Therefore pounds of protein in the soybeans = 0.16*S.

Answer 12

oh. I was putting 16s ... but it's 0.16s

Answer 13

You could use 16S, but then you'd have to set it equal to 12*350.
It would work out the same, you just need to be careful about consistency.

Answer 14

Ok. Lets see if i can figure out now

Answer 15

Im stuck as to how to figure this out

Answer 16

equation one: total pounds of mixture
S + C = 350
equation two: total pounds of protein in mixture
0.16S + 0.09C = 0.12*350

Answer 17

ok. I did not have eq 2 that way. All I had was .16s+.09c=.12

Answer 18

why are we multiplying 12 by 350 on 2nd equation

Answer 19

Because that equation is in terms of the pounds of protein in the mix.
The total mix weight is 350 pounds, 12% of which is protein.

Answer 20

Ok, i think i understand. let me try to figure again

Answer 21

s = 150 and c =200

Answer 22

Yes, those are correct.

Answer 23

Ok. I'm closing this question and opening another. I hate word problems. If you can help I would appreciate it and give you another medal. Thanks