Question

Is there a rule to how long you should wait until reposting something? I would really like to get this question out of the way ^^;

Answer 1

one rule says 3 days :)

Answer 2

If you can't see it in a full scroll, you can go ahead and re-post Particularly if you are going to be around to work with a tutor immediately.

Answer 3

Alright, thanks.

Answer 4

Is this the question?


Pistachios cost $6.50/pound and Almonds cost $8.00/pound. How much of each to make a 50lb mixture that costs $7.50/pound?

Any help in the right direction would be great!

Answer 5

Yes, it is.

Answer 6

Ok well Lets use P for the amount of pistachios and A for the amount of almonds.

Answer 7

So the resulting 50 pounds relates to P and A how?

Answer 8

ill abstract it just so as not to stir the kettle to bad lol

a+b = t; a = t-b

ax + by = tz

(t-b)x + by = tz

tx -bx + by = tz

-bx + by = tz - tx

b(y-x) = t(z-x)

b@y = t(z-x)/(y-x) ; :)

Answer 9

lol, I know how to do this and even I can't make sense of that amistre ;p

Answer 10

I believe something like: 6.50p + 8.00a = 50

Answer 11

ooh, good guess

Answer 12

But look at the unit analysis.

Answer 13

Not sure what unit analysis is. ^^;

Answer 14

6.5(dollars/pound) * p (pounds) + 8(dollars/pound) * a (pounds) = dollars

But you equated them to 50 pounds

Answer 15

another method I got brewing in me head is:

a+ b = t ; multiply by say, -x
xa + yb = tz

-xa - xb = -tx
xa + yb = tz
--------------
b(y-x) = t(z-x) ... lol, it comes out the same

Answer 16

Oh, I see. So we need: 6.50p + 8.00a = 7.40?

Answer 17

but 7.5 is in dollars/pound not just dollars

Answer 18

so how many dollars will 50 pounds of the mixture be if it's 7.5 dollars per pound?

Answer 19

370

Answer 20

good!

Answer 21

So now we can solve for the amount of one in terms of the other.

Answer 22

But we still need to know something more.

Answer 23

How so? It's 7.40 per pound, not 7.50

Answer 24

"How much of each to make a 50lb mixture that costs $7.50/pound?"

Answer 25

Oh! I'm sorry, I typo'd the first post. It's 7.40 per not 7.50!

Answer 26

oh, well then make the appropriate adjustment.

Answer 27

So we have now: 6.50p + 8.00a = 370?

Answer 28

So would I use the subsitution method to solve for one of the variables?

Answer 29

Well yes, but we need one more equation to be able to substitute.

Answer 30

That's true, lol.

Answer 31

We have 1 equation and 2 unknowns.

But let me ask you this. That 50 pounds we were talking about earlier. How does it relate to P and A?

Answer 32

Because the 50 pounds is a mix of P (Pistachios) and A (Almonds) to equal 50lbs?

Answer 33

Right. so can we use that to write another equation?

Answer 34

P is in units of?

Answer 35

We said that P was the 'amount' of pistachos, but really what do we mean by 'amount'?

Answer 36

By amount we mean pounds I believe. So we have x pounds of P.

Answer 37

No, we have P pounds of pistachios

Answer 38

Ah, hmm, lets see.

Answer 39

But yes, it's in pounds. So if we take the pounds of pistachios and the pounds of almonds what is the relation to the final weight of the mixture?

Answer 40

AllI can think of is that they have the relation that together they = 50lb but we already knew that.

Answer 41

Quick question: Would we want to take the decimals out of this equation?

Answer 42

I apologize for the abrupt leave but I must go. I hope we can pick this up at a later time. Thank you for your help so far. Glad I found this place!

Answer 43

AllI can think of is that they have the relation that together they = 50lb but we already knew that.

We do know this, but we haven't used it yet! This is the second equation we need:

P + A = 50

Answer 44

As for the decimals, you can keep them or just multiply the whole equation by 10 it amounts to the same thing.

Answer 45

Sorry for not getting back to you sooner, I had a phone call. Hopefully you'll see this later.