SOLUTION: You need 765 mL of a 30% alcohol solution. On hand, you have a 85% alcohol mixture. How much of the 85% alcohol mixture and pure water will you need to obtain the desired solution?

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: You need 765 mL of a 30% alcohol solution. On hand, you have a 85% alcohol mixture. How much of the 85% alcohol mixture and pure water will you need to obtain the desired solution?      Log On

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Question 838391: You need 765 mL of a 30% alcohol solution. On hand, you have a 85% alcohol mixture. How much of the 85% alcohol mixture and pure water will you need to obtain the desired solution?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
How much of the 85% alcohol mixture(15% water) and pure water
to make 765 mL of a 30% alcohol solution (70% water)
Let x represent the ml of water needed to be added
water = water
.15%2A%28765-x%29++%2B+x+=+.70%2A765%29
x+=+%28.55%2A765%29%2F.85+ x = 495ml of water need to be added