<PRE><B>Question 401189</B>
A car radiator has a 16 quart capacity and is currently filled with a 40% antifreeze solution.  How many quarts of this solution must be drained off and replaced with 100% antifreeze to create a 50% antifreeze solution?
.
Let x = amount (quarts) to be drained and replaced
then
.40(16-x) + x = .50(16)
6.4-.40x + x = 8
6.4 + .60x = 8
.60x = 1.6
x = 1.6/.60
x = 2.67 quarts
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