SOLUTION: David needs to have a 20% solution of antifreeze and water in his radiator. If the radiator of truck contains 8 quarts of a solution of antifreeze and water, with 10% being antifre

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Question 982455: David needs to have a 20% solution of antifreeze and water in his radiator. If the radiator of truck contains 8 quarts of a solution of antifreeze and water, with 10% being antifreeze, how much antifreeze must be added to create the desired solution?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
The description implies that the capacity of the radiator is greater, larger than 8 quarts.

Has 10%; wants or needs 20%;

Let v be amount of pure antifreeze to add.
%288%2A%280.1%29%2Bv%2A%281.0%29%29%2F%28v%2B8%29=0.2, setup using decimal fractions instead of percents;

%288%2B10v%29%2F%28v%2B8%29=2, simply multiplied both sides by 10

10v%2B8=2%28v%2B8%29
and again,...

5v%2B4=v%2B8

v%2B4=8

highlight%28v=4%29, how many quarts of pure antifreeze to add.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

David needs to have a 20% solution of antifreeze and water in his radiator. If the radiator of truck contains 8 quarts of a solution of antifreeze and water, with 10% being antifreeze, how much antifreeze must be added to create the desired solution?
Amount of antifreeze to add: highlight_green%281%29 quart