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Topic: Systems of Linear Equations
Replies: 6   Last Post: Jan 29, 2011 10:13 PM

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William Elliot

Posts: 1,948
Registered: 5/30/08
Re: Systems of Linear Equations
Posted: Jan 28, 2011 10:29 PM
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On Fri, 28 Jan 2011, mathematicsstudent wrote:

> The manager of a bulk foods establishment sells a trail mix for $8 per
> pound and premium cashews for $15 per pound. The manager wishes to make
> a 105-pound trail mix-cashew mixture that will sell for $12 per pound.
> How many pounds of each should be used?
> I figured out that the first equation should be:
> X + Y = 105
> How do I write the other equation? I tried this, but it didn't work:
> 08x + .15Y = 12

08 looks like a mistake. Did you mean .08?
No. More sense is 8x + 15y = 12.

8$/lb * x lb + 15$/lb * y lb = 12$/lb

The dimensions aren't correct.
The left hand side is dollars and the
right hand side is dollars per pound.

Where did the notion of 15%, ie .15 come from?

> If you can guide me along, I would greatly appreciate it!

8$/lb * x lb + 15$/lb * y lb = 12$/lb * how many lbs?
= cost of the mix.

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