SOLUTION: How many mililiters of 70% isopropyl alcohol should be mixed with 20 mililiters of water to make 50% isopropyl alcohol?

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Question 422077: How many mililiters of 70% isopropyl alcohol should be mixed with 20 mililiters of water to make 50% isopropyl alcohol?
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
.7(x)+20=.5(x+20)
.7x+20=.5x+10
.2x=10
x=10/.2=50
50 mL of 70% alcohol need to be mixed with pure water to make 70 mL of 50% alcohol..