Question 558198
<pre>
PERCENT COPPER         QUANTITY          PURE COPPER

   40                     x                 0.4x
   80                    500 oz.            0.8*500

   60                    x+500              0.4x+0.8*500
</pre>
{{{highlight_green((0.4x+0.8*500)/(x+500)=0.6)}}}


{{{0.4x+0.8*500=0.6(x+500)}}}

{{{0.4x+0.8*500=0.6x+0.6*500}}}

{{{0.8*500-0.6*500=0.6x-0.4x}}}

{{{500(0.8-0.6)=(0.6-0.4)x}}}


{{{highlight(x=500((0.8-0.6)/(0.6-0.4)))}}}
Compute this.