SOLUTION: How many liters of a 10% alcohol solution must be added to 80 liters of a 30% alcohol solution to obtain a 15% alcohol solution? Please Help!!!

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Question 14307: How many liters of a 10% alcohol solution must be added to 80 liters of a 30% alcohol solution to obtain a 15% alcohol solution? Please Help!!!
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You can write the equation to solve this problem like this:
(10%)x liters + (30%)80 liters = (15%)(x+80)liters. Change the percents to decimals.
0.1x+%2B+%280.3%2980+=+%280.15%29%28x%2B80%29 Simplify and solve for x.
0.1x+%2B+24+=+0.15x+%2B+12 Subtract 12 from both sides.
0.1x+%2B+12+=+0.15x Subtract 0.1x from both sides.
12+=+0.05x Finally, divide both sides by 0.05
240+=+x
240 liters of 10% alcohol solution must be added to the 80 liters of the 30% alcohol solution to obtain 320 liters of 15% alcohol solution.