Question 668853
How many litters of pure alcohol must be added to 15 litters of a 60% alcohol solution to obtain an 80% alcohol solution?
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let x=amt of pure alcohol to be added
..
100%x+60%*15=80%(x+15)
x+9=.8x+12
.2x=3
x=15
amt of pure alcohol to be added=15 liters