SOLUTION: A pharmacist mixed some 10% saline solution with some 15% saline solution to obtain 100mL of a 12% saline solution. How much of the 10% saline solution did th pharmacist use in the

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: A pharmacist mixed some 10% saline solution with some 15% saline solution to obtain 100mL of a 12% saline solution. How much of the 10% saline solution did th pharmacist use in the      Log On


   

Question 192294: A pharmacist mixed some 10% saline solution with some 15% saline solution to obtain 100mL of a 12% saline solution. How much of the 10% saline solution did th pharmacist use in the mixture?
Answer by stanbon(75887) About Me  (Show Source):
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A pharmacist mixed some 10% saline solution with some 15% saline solution to obtain 100mL of a 12% saline solution. How much of the 10% saline solution did th pharmacist use in the mixture?
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Equation:
saline + saline = saline
0.10x + 0.15(100-x) = 0.12*100
Multiply thru by 100 to get:
10x + 15*100 - 15x = 12*100
-5x = -3*100
x = 60mL (amt. of 10% solution in the mixture)
100-60 = 40mL (amt. of 15% solution in the mixture)
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Cheers,
Stan H.