Ot-Need help from someone good in math please

neverbeanother#7 · Jan 29, 2007

Ok, I am trying to figure something out but for some reason my brain is not registering. It is either:

1. Too damn cold here in upstate NY and my brain froze.
2. It's too early in the morning.
3. I am a moron

Anyways, Here is what i am trying to figure out. I have a bunch of scrap gold that i am taking to the refiners today and am trying to figure out the average karat percentage of the lot so i have it to compare with what the refiner assays it as.For some reason i can't figure out how to do it.

I have:
131.5 grams 10k (41.7% pure gold)
247 grams 14k (58.5% pure gold)
58.5 grams 18k ( 75% pure gold)
21 grams 21k (87.5% pure gold)

So basically what i am looking for is the average percentage to fill in this sentence.

I have 458 grams of gold @ a pure gold percentage of _______.
Thanks in advance to all those who can help. :103631605

Btw, If you chose answer 3 you probably win the prize.

DrChen · Jan 29, 2007

I think it is 57.11%

gynecologist · Jan 29, 2007

57.675% ???

Actually I have no idea.. But I'm sure someone will be able to help you here.

DrChen · Jan 29, 2007

Basically, out of 458 grams of whatever you've got, 261.58 grams of it is pure gold. So I just divided 261.58 by 458

gynecologist · Jan 29, 2007

DrChen said:
Basically, out of 458 grams of whatever you've got, 261.58 grams of it is pure gold. So I just divided 261.58 by 458

Tried doing the same thing but messed up somewhere with the math. Did it again slower and came up with 57.11% as well..

neverbeanother#7 · Jan 29, 2007

Thanks guys!! I appreciate it. If the consensus is both % 57.11 thats good enough for me.

ganchrow · Jan 29, 2007

If you wanted to be precise, it actually comes out to 57.01%.

That's because you're calling 14k gold 58.5% pure, when in fact it's only 58<sup>1</sup>/<sub>3</sub>%.