+1090 Six millimeters of a ten percent acid solution is mixed with nine millimeters of a twenty percent acid solution. What is the resulting concentration?
($$\mathrm{A.}$$ $${\mathtt{18}}\%$$ $$\mathrm{B.}$$ $${\mathtt{16}}\%$$ $$\mathrm{C.}$$ $${\mathtt{17}}$$ $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}$$% $$\mathrm{D.}$$ $${\mathtt{16}}$$ $${\frac{{\mathtt{2}}}{{\mathtt{3}}}}$$% $$\mathrm{E.}$$ $$\mathrm{NOT}$$)
+118673 Mathematician,
It is not a good idea to give negative points when people seriously try to help you.
If you know that the answer is incorrect of if you want to ask questions about their answer then add another post to explain what you are thinking.
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+129852 The total amount of acid in both solutions is (6 + 9)ml = (15)ml
And if 6ml is 10% of the first mixture, then there are 60ml total in the first mixture. And if 9ml is 20% of the second solution, there must be 45ml total in the second mixture.
So (6+9) / (60 + 45) = 15/105 = about 14.2%......E is the correct answer.....
+23252 I get a different answer because I'm interpreting the problem differently; I'm interpreting "six milliliters of a ten percent solution" to mean that the total amount of this solution is 6 ml and 10% of that amount is acid.
Total amount when the two are mixed = 15 ml.
Using the formula:
(Amount)·(Percentage) + (Amount)·(Percentage) = (Total Amount)·(Total Percentage)
(6)·(.10) + (9)·(.20) = (15)·(x)
.60 + 1.80 = 15x
2.40 = 15x
0.16 = x ---> Answer B
+129852 Ah...I see what you mean...I did interpret this a little differently......I have a feeling that yours might be correct.......
+118673 Mathematician,
It is not a good idea to give negative points when people seriously try to help you.
If you know that the answer is incorrect of if you want to ask questions about their answer then add another post to explain what you are thinking.
We like people to be interactive with answering.
+1090 Giving negative points was never my intent. I think I must of accidently downpointed CPhil.
+129852 HAHAHA!!!!....I don't give a hoot about "points"......I just interpreted the situation a little differently from geno....however, since most of the responses seem to be "clustered" around his answer, I think he was on the correct trail........maybe I need to improve my reading comprehension....LOL!!!
