SOLUTION: Hello
I need help with a solution problem. I can not seem to put this thing together.
A pharmacist is to prepare 15 milliliters of special eye drops for a glaucoma patien
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I need help with a solution problem. I can not seem to put this thing together.
A pharmacist is to prepare 15 milliliters of special eye drops for a glaucoma patien
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Question 30391: Hello
I need help with a solution problem. I can not seem to put this thing together.
A pharmacist is to prepare 15 milliliters of special eye drops for a glaucoma patient. The eye-drop solution must have a 2% active ingredient, but the pharmacist only has 10% solution and 1% solution in stock. How much of each type of solution should be used to fill the prescription.
Help with this will be greatly appreciated, I am lost on this one.
Thanks
Terry Answer by longjonsilver(2297) (Show Source):
Second, just looking at the question, we have some 10% and some 1% that mix to make a 2% solution.
Just by common sense, we will need more of the 1% solution, since the final answer is a 2% solution. Hoepfully that makes sense? We expect a lot more of the 1% solution to be used.
Right...
Let x = amount of 1% solution used.
So, how much of 10% is used? Answer is (15-x) --> ie everything else to make up the final 15ml.
BEFORE: x of 1% AND (15-x) of 10%
--> 0.01x + 0.10(15-x)
AFTER: 15ml of 2%
--> 0.02*15
And being a mixture, the BEFORE has to equal the AFTER:
0.01x + 0.10(15-x) = 0.02*15
0.01x + 1.5 - 0.10x = 0.30
-0.09x = -1.2
x = -1.2/-0.09
x = 13.3333 ml
and so there are 13.3333ml of the 1% solution and 1.6666ml of the 10% solution.
