Question 1015898
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x=quarts of pure antifreeze to add
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0.20(6)+x=0.40(6+x)
1.2+x=2.4+0.40x . Subtract (0.40x) from each side.
1.2+0.60x=2.4 . Subtract 1.2 from each side. 
0.60x=1.2 . Divide each side by (0.60)
x=2

ANSWER: You should add 2 quarts of pure antifreeze.
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