Answer:
your answer is y =-8 hopes this help
Answer:
58.33 lbs.
Step-by-step explanation:
There are already 25 lbs of alloy of copper
Of this 25 lbs, 20% is pure i.e. copper content = 25(0.5) = 5lbs.
Now available is
Copper Other metals
5 lbs 20 lbs
Let x lb of 30% copper is added.
Then new alloy will have 5+0.3x lb copper in total of 25+x lbs
Percentage pure = 
Simplify to get

Hence answer is 58.33 lbs should be added.
It is the fourth option, y+8=3(x-8)
Just by simply adding the two quantities you can get the net change. $67.12 +(addition sign because we want the net change) $2.56= $69.68. The last number is the net change!