<PRE><B>Question 507316</B>
how many liters should be drained and replaced with pure antifreeze from a radiator containing 12 liters of 40 percent antifreeze to increase the concentration to 50 percent antifreeze.
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alcohol - alcohol + alcohol = alcohol
0.40*12 - 0.40x + 1.0x = 0.50*12
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Multiply thru by 100 to get:
40*12 - 40x + 100x = 50*12
60x = 10*12
x = 2 liters (amt. to be replaced by pure antifreeze)
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Cheers,
Stan H.</PRE>