Question

How much of an alloy that is 10% copper should be mixed with 600 ounces of an alloy that is 60% copper in order to get an alloy that is 20% copper?

Answer 1

1800 oz.

Explanation:

There are already 600 ounces of alloy of nickel.

Of this 600 oz, 50% is pure i.e. copper content = 600(0.5) = 300 oz

Now available is

Copper Other metals

300 300

Let x oz of 10% copper is added.

Then new alloy will have 300+0.1x oz copper in total of 600+x oz.

Percentage pure =
`(300+0.1x)/(600+x) =20%`

Simplify to get

`(300+0.1x)/(600+x) =(20)/(100) \\\\Cross multiply:\\20(600+x) =100(300+0.1x)\\12000+20x =30000+10x\\10x = 18000\\x = 1800`

Hence answer is 1800 oz should be added.