Question 335765: I'm stuck on a problem I'm working on. The question is about an automobile with a 16L tank, which 30% is antifreeze. The problem asks how much needs to be taken out of the mixture and how much pure antifreeze must be added so the tank has 50% antifreeze. I know I need to use a system of equations but I'm stuck on what the equations are.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The question is about an automobile with a 16L tank, which 30% is antifreeze. The problem asks how much needs to be taken out of the mixture and how much pure antifreeze must be added so the tank has 50% antifreeze.
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Equation:
alcohol - alcohol + alcohol = alcohol
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0.30*16-0.30x+ 1.00x = 0.50*16
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Multiply thru by 100 to get:
30*16 - 30x + 100x = 50*16
70x = 20*16
x = (2/7)16
x = 4.57 liters (amt. of 30% liquid that must be replaced by 100% liquid)
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Cheers,
Stan H.
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