ok. this involves simultaneous equations.
first you need to work out what are the equations. for the first equation, you work out how much protein from both oats and cornmeal to make 260grams. so..
if x = oz of oats, and y = oz of cornmeal
the equation will be:
5x+3y = 260......(eq 1)
and do the same for carbohydrates to eqaul 1505 grams:
if x = oz of oats, and y = oz of cornmeal
the equation will be:
17x+24y = 1505......(eq 2)
now you have to eliminate one of the pronumerals (x or y) so you can find one of them, which will help in finding the other. to do this, you see if one of the terms are the same in each equation. in this case, there isnt. so you multiply one of the equations so a term appears in both. in this example, lets multiply [eq. 1] by 8, because if we multiply 3y by 8, we get 24y, which is found in eq. 2.
so...
eq 1: (5x+3y = 260) x 8
= 40x+24y = 2080.
now we can subtract [eq. 1] from [eq. 2] to find x.
so...
eq 1: 40x+24y = 2080.
eq 2: 17x+24y = 1505.
[eq. 2] minus [eq. 1]
17x + 24y - (40x+24y) = 1505 - 2080
17x - 40x + 24y -24y = -575
-23x = -575
x = 25
now you can sub x into one of the equations (lets make it eq 1, because its easier) to find y.
so...
eq 1: 5x+3y = 260
sub x = 25
5(25)+3y = 260
125+3y = 260
3y = 135
y = 45
So you have your answers:
if x = 25 oz of oats and y = 45 oz of cornmeal....TA DA!!
I know this may be a VERY LONG explanation, but i just want to make sure i was clear, and so you know what's happening.
Post edited at 1:43 am on April 24, 2008 by qwerky
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So long and thanks for all the fish!