SOLUTION: Hello, I was wondering if you could help me with this math problem. The question is "Pure copper was mixed with 34 kg of a 12% copper alloy to produce a new alloy that is 32% coppe

Algebra.Com
Question 924971: Hello, I was wondering if you could help me with this math problem. The question is "Pure copper was mixed with 34 kg of a 12% copper alloy to produce a new alloy that is 32% copper. How much of the pure copper was used to make the new alloy?"
I tried to work the problem out with an equation, but I could not get the correct equation.
Anything would help. I am so lost.
Thanks!
Found 2 solutions by ptaylor, jim_thompson5910:
Answer by ptaylor(2198)   (Show Source): You can put this solution on YOUR website!
Sure
Let x=amount of pure copper needed
Now we know that the amount of pure copper that exists before the mixture takes place (x+0.12*34) has to equal the amount of pure copper that exists after the mixture takes place (0.32*(34+x)). Soooo our equation to solve is:
x+0.12*34=0.32(34+x)
You solve
Hope this helps---ptaylor
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Go straight to their question: "How much of the pure copper was used to make the new alloy?"

So they want to know how much pure copper to use. For now, we don't know it, so let's make

x = amount of pure copper (in kg)

We'll be adding x kg of pure copper

-------------------------------------------------------

We already have " 34 kg of a 12% copper alloy", so 34*0.12 = 4.08 kg of pure copper is already there.

We add x kg of pure copper to 4.08 kg to get x+4.08

In total, we have x+4.08 kg of pure copper.

-------------------------------------------------------

We are adding x kg of pure copper to be mixed with the 34 kg of copper alloy. So we'll have a total of x+34 copper alloy (copper + other stuff)

-------------------------------------------------------

Divide the two expressions to get



The expression must be set equal to 0.32 because we want the final alloy to be 32% copper.



-------------------------------------------------------

Solve for x.


























-------------------------------------------------------


Answer:


You must add 10 kg of pure copper.

------------------------------------------------------------------------

Let me know if that helps or not. Thanks.

If you need more help, feel free to email me at jim_thompson5910@hotmail.com

My Website: http://www.freewebs.com/jimthompson5910/home.html

RELATED QUESTIONS

I have been struggling with this problem for a while now and I was wondering if anyone... (answered by josmiceli)
Pure copper was mixed with a 12% alloy to produce an alloy that was 20% copper. How much... (answered by Maths68)
Hello, I was wondering if someone could help me with this math question: Write the... (answered by flame8855,scott8148)
Hello, i was wondering if anyone could help me with this one problem. I did get an... (answered by stanbon)
hello, i was wondering if someone could help me with this problem. "write the equation of (answered by sofiyac)
Pure copper was mixed with a 12% copper alloy to produce an alloy that was 32% copper.... (answered by mananth)
hi, I was going through my math homework and i was wondering if you could help me with... (answered by josgarithmetic)
Hello. I was wondering if you could please assist me with this math problem. I've been... (answered by stanbon)
I have been working on this math problem and i can't seem to figure it out. I was... (answered by Alan3354,richwmiller)