SOLUTION: A tank contains 20 gallons of a 30% antifreeze solution. How many gallons of an 80% antifreeze solution shoul be added to the tank in order to have the concentration of the antifr

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Question 193629: A tank contains 20 gallons of a 30% antifreeze solution. How many gallons of an 80% antifreeze solution shoul be added to the tank in order to have the concentration of the antifreeze in the tank increase to 50%?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
.30*20+.80x=.5(20+x)
6+.8x=10+.5x
.8x-.5x=10-6
.3x=4
x=13.33 gal of 80% solution is needed.
Proof:
.30*20+.8*13.33=.5(20+13.33)
6+10.66=.5*33.33
16.66=16.66