Question 910167
How many gallons of 25% alcohol solution and 40% alcohol solution must be mixed to get 9 gallons of 30% alcohol solution? 
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let x=amt of 25% solution to mix
9-x=amt of 40% solution to mix
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25%x+40%(9-x)=30%*9
.25x+3.6-.40x=2.7
.15x=0.90
x=6
9-x=3
amt of 25% solution to mix=6 gal
amt of 40% solution to mix=3 gal