Trying to help out the kid, but math and I never got along.
If I have a 30% solution and a 5% solution, how do I create 35ml of a 12% solution from them?
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Trying to help out the kid, but math and I never got along.
If I have a 30% solution and a 5% solution, how do I create 35ml of a 12% solution from them?
i feel stupid, i can't figure it out! glad i'm not in a math related field
Looks like 2 equations and 2 unknowns...Quote:
Originally Posted by jibij
30x + 5y = 12
x + y = 35
Right now I am watching A Few Dollars More. I wonder how Clint Eastwood would answer this question....
.3*x + .05*(35-x) = .12*35Quote:
Originally Posted by jibij
Solve for x, where x is the volume of the 30% solution. Should work, but you might want to check in with BigKuba - he's the one with a degree in chemical engineering from MIT.
35*0.12 = (35-x)*0.30 + x*0.05
solving for x you get 25.2ml of 5% solution and 9.8ml of 30% solution I think.
Holy crap. The potential answers are more confusing than the question. Trying to cipher out the nhtele/dima solution.
A 30% solution of what and a 5% solution of what to make 35 mls of a 12% solution of what?Quote:
Originally Posted by jibij
Methamphetamines... its all the middle schoolers are cooking these days.Quote:
Originally Posted by Viva
acid solutionQuote:
Originally Posted by Viva
nhtele and spanky are both saying the same thing id differnt ways. nhtele's might be easier for a grade 8 to understand though.
finally 5 years of an honors math degree amounts to something!
What acids? The same acid? Fuck! Dilute the 30% soln. to 12% and be done with it! Whats that? Hang on...14 ml of the 30% + 21 mls HOH. Is that right? Fuck, i used to do this shit in my head everyday. I think I;ll have another beer now.Quote:
Originally Posted by jibij
Well, thell them to stop it, god dammit! It's bad for their teeth.Quote:
Originally Posted by FigureEleven
Your kid must be smart. I'm pretty sure I wasn't doing shit like that in 8th grade.
Thats a tough one, cant help, I could assist in any joint rolling questions the lad might have.
What age is 8th grade?
Just be sure to do it under a hood and wear gloves.Quote:
Originally Posted by Viva
like 13ishQuote:
Originally Posted by Mr.Scruff
nhtele is right
dima is right
Spanky's first equation should be 30x + 5y = 420
In long form, here's how to figure it out:
You are trying to get to 35 ml of 12% solution. That means when you're done mixing the the components you end up with 35 ml of liquid, and 4.2 ml (12% of 35 ml) of stuff dissolved in it.
If x is the volume of the 30% solution, and y is the volume of 5% solution, you know two things:
Total volume of the two solutions added together will be 35 ml. Therefore:
x + y = 35
Total volume of dissolved stuff will be 4.2 ml. The volume of dissolved stuff in the 30% solution is (0.30 * x), and the volume of dissolved stuff in the 5% solution is (0.05 * y). Therefore:
(0.30 * x) + (0.05 * y) = 4.2
From the first equation, we know that:
y = 35 - x
Substitute that into the second equation, and you get:
0.30 * x + 0.05 * (35 - x) = 4.2
0.30 * x + 0.05 * x - 0.05 * 35 = 4.2
0.25 * x - 1.75 = 4.2
0.25 * x = 2.45
x = 9.8
y = 25.2
Bacon...Quote:
Originally Posted by Viva
my cat's breath smells like catfood.
http://www.filmica.com/casiopea/archivos/ralph1.jpg
Only correction to The Suit (sorry, I'm nit-picky) is that Spanky's first equation should be: .30x + .05y = 4.20 (since we're dealing with percentages).
They're the same. Just multiply both sides by 100. Since Spanky had started out with 30x + 5y, I went with it. You get the right answer either way.Quote:
Originally Posted by GoldMember
Yeah, I know. I said I was being nit-picky! (Sorry, it's my nature....)
Its also alot easier to deal with whole numbers than percentages or decimals.