Question 1076579
The fraction is Zn/Cu+Zn
right now it is 50/150, if 150 pounds of both and 100 pounds of Cu, the rest has to be Zn. Let x=pounds of copper added
50/(100+x+50)=0.1
50/(150+x)=0.1
50=15+0.1x
35=0.1x
x=350 pounds of copper
At that point, the alloy will weigh 500 pounds, 50 of which will be zinc.