# Thread: Simple Problem

1. ## Simple Problem

Q. Clock brass consists of 64.25% copper, 34% zinc and 1.75% lead. A manufacturer has an unlimited supply of copper and lead but has only 50kg of zinc. How much closs brass can he make?

Simple problem but I just can't get the answer.

Please show your working out and don't just give the answer.
Thanks.

2. I think you are missing a piece of information. What is the mass of each clock brass.

3. You will want to set up a proportion.

So $\frac {34}{100}$ = $\frac{50}{x}$

Then you cross multiply to get $\frac{54*100}{34}$= x

So x $\approx$158.82353 and there is your answer.

4. Originally Posted by JoshHJ
You will want to set up a proportion.

So $\frac {34}{100}$ = $\frac{50}{x}$

Then you cross multiply to get $\frac{54*100}{34}$= x

So x $\approx$158.82353 and there is your answer.
Edit:
My bad, I misread the problem.

you cross multiplied wrong
It should be
$\frac{50*100}{34}$= x
x=147

5. OK I get it now. Thanks.

6. Originally Posted by Linnus
Edit:
My bad, I misread the problem.

you cross multiplied wrong
It should be
$\frac{50*100}{34}$= x
x=147
Hah, yeah. It's getting too late, and I have no idea where the 54 came from.