SOLUTION: A vessel contains 2 liters of alcohol and 28 liters of water.How many liters of alcohol must be added to make the new mixture 12.5% alcohol?

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Question 1062641: A vessel contains 2 liters of alcohol and 28 liters of water.How many liters of alcohol must be added to make the new mixture 12.5% alcohol?
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
After we add x liters of alcohol, 

1.  we will then have 2+x liters of alcohol.

And since alcohol is liquid, we begin with 28+2 liters
of liquid, and when we add x more liters of liquid alcohol,

2.  we will then have 28+2+x liters of liquid.

expr%28%282%2Bx%29%2F%2828%2B2%2Bx%29%29%2A%22100%25%22%22%22=%22%2212.5

expr%28%282%2Bx%29%2F%2830%2Bx%29%29%2A%22100%25%22%22%22=%22%2212.5

Multiply both sides by 30+x:

%282%2Bx%29%2A%22100%25%22%22%22=%22%2212.5%2830%2Bx%29

200%2B100x%22%22=%22%22375%2B12.5x

100x-12.5x%22%22=%22%22375-200

87.5x%22%22=%22%22175

x%22%22=%22%22175%2F87.5

x%22%22=%22%221750%2F875

x%22%22=%22%222 liters of alcohol.

Edwin