SOLUTION: How much water should be added to 16 mL of 20% alcohol solution to reduce the concentration to 8%?

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Question 225460: How much water should be added to 16 mL of 20% alcohol solution to reduce the concentration to 8%?
Found 2 solutions by josmiceli, checkley77:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = amount of water to be added
The solution has .2%2A16+=+3.2 ml of alcohol in it
3.2%2F%2816+%2B+x%29+=+.08
3.2+=+.08%2A%2816+%2B+x%29
3.2+=+1.28+%2B+.08x
.08x+=+1.92
x+=+24
24 ml of water must be added

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
.20*16=.08(16+X)
3.2=1.28+.08X
.08X=3.2-1.28
.08X=1.92
X=1.92/.08
X=24 ML OF WATER IS USED.
PROOF:
.20*16=.08(16+24)
3.2=.08*40
3.2=3.2