Question 524004
A health food store sells oatmeal for $3.60 per pound and bran flakes for $4.80 per pound. How many pounds of each should be used to get a mixture of 30 pounds that sells for $4.00 a pound?
<pre>
First you have the AMOUNT OF CEREAL equation:

{{{(matrix(5,1,
Number,
of, 
pounds,
of,
oatmeal))}}}+{{{(matrix(6,1,
Number,
of, 
pounds,
of,
bran,
flakes))}}}={{{(matrix(6,1,
Number,
of, 
pounds,
of,
cereal,
mixture))}}} or x + y = 30  

And second, you have the AMOUNT OF MONEY equation:

{{{(matrix(7,1,
Number,
of, 
pounds,
of,
oatmeal,
times,
"$3.60"))}}}+{{{(matrix(8,1,
Number,
of, 
pounds,
of,
bran,
flakes,
times,
"$4.80"))}}}={{{(matrix(8,1,
Number,
of, 
pounds,
of,
cereal,
mixture,
times,
"$4.00"))}}} or (x)(3.60) + (y)(4.80) = (30)(4.00) or 3.6x + 4.8y = 120

So you have this system of equations:

x + y = 30
3.6x + 4.8y = 120 

Solve that system and get x = 20 and y = 10.

Answer: 20 pounds of oatmeal and 10 pounds of bran flakes. 

Edwin</pre>