SOLUTION: Please help me on this problem. I spent 3 hours on it and I still am having trouble on it. A metal worker is trying to create a copper alloy . He has two different type of metals

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Question 739405: Please help me on this problem. I spent 3 hours on it and I still am having trouble on it.
A metal worker is trying to create a copper alloy . He has two different type of metals. One is 20% copper and the other one is 60% metal. He is trying to make a 52% copper alloy and weighs 80 kg. Create a liner system and solve.
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
A metal worker is trying to create a copper alloy .
He has two different type of metals.
One is 20% copper and the other one is 60% copper.
He is trying to make a 52% copper alloy and weighs 80 kg.
:
let a = amt of 20% copper metal
let b = amt of 60% copper metal
:
The amt equation:
a + b = 80
a = (80-b), use this form for substitution
:
The percent equation in decimal form
.20a + .60b = .52(80)
.20a + .60b = 41.6
replace a with (80-b)
.20(80-b) + .60b = 41.6
16 - .20b + .60b = 41.6
.40b = 41.6 - 16
b = 25.6/.4
b = 64 kg of 60% copper
:
I'll let you find how much 20% copper is required
check it in the percent equation