SOLUTION: Hi...my cousin asked me to help him with this math problem... "The metal in the wires of Christmas lights is a combination of copper and lead. The State of California requires a

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Question 389537: Hi...my cousin asked me to help him with this math problem...
"The metal in the wires of Christmas lights is a combination of copper and lead. The State of California requires a warning label for any product that contains 25% or more lead. The current batch of metal for the wiring consists of 45% lead and weighs 2200 pounds. How many pounds of a 85% copper - 15% lead mixture should be added to avoid placing the label on the lights?"
Oh my...lol...help...lol...thanks...*smiles*
I tried this one equation with 24% and got about 4911 pounds, and then I used 25% and I got 4400 pounds...?
Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
You want to end up with less than 25% lead, so
Let = pounds of mixture to be added
In words:
(pounds of lead in final mixture)/(total pounds of mixture) = 25%

You must add more than 4400 pounds of mixture
To check, I'll add 4401 pounds

looks right