<PRE><B>Question 938632</B>
How much pure antifreeze must be added to 4.5 gallons of a 30% antifreeze solution to obtain a 40% antifreeze solution? 
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Equation:
anti + anti = anti
0.30*4.5 + 1*x = 0.40(4.5+x)
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30*4.5 + 100x = 40*4.5 + 40x
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60x = 10*4.5
x = (1/6)4.5
x = 0.75 gallons (amt. of pure anti-freeze to add)
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Cheers,
Stan H.
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