SOLUTION: How many gallons of pure antifreeze must be mixed with 30 gallons of 15% antifreeze to get a mixture that is 40% antifreeze ?

Question 733274:
How many gallons of pure antifreeze must be mixed with 30 gallons of 15% antifreeze to get a mixture that is 40% antifreeze ?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
How many gallons of pure antifreeze must be mixed with 30 gallons of 15% antifreeze to get a mixture that is 40% antifreeze ?
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Equation:
anti + anti = anti
1*x + 0.15*30 = 0.40(x+30)
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100x + 15*30 = 40x + 40*30
60x = 25*30
x = 12.5 gallons (amt. of pure anti to add)
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Cheers,
Stan H.
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