Query about Question 2 from "(I'm Overwhelmed) Algebra Progress Quiz #6 (Version 2)" [7617]

[user6613]

https://www.gregmat.com/quizzes/quiz/im-overwhelmed-algebra-progress-quiz-6-version-2 (Question 2)

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I got this question incorrect because, based on my interpretation of the study plan videos, I thought that we were supposed to consider the part of the mixture that the question inquires about. I didn’t think we were also supposed to include water (in liters) as part of the total. For instance, in the second screenshot from the Mixture Problems Video, Greg only takes into account the oxygen and disregards the nitrogen.

[LemonIceTea9]

If the question stated that only drink A and drink B were mixed, you could use the mixture trick.

But there is also pure water being added to the mix, and that will throw the ratio out of proportion.

You can use a tabular method.

Column 1	Column 2	Column 3	Column 4
	Alcohol	Water	Total
Mix A	0.5 (25% of total)	1.5 (75% of total)	2
Mix B	2 (40% of total)	3 (60% of total)	5
Additional		3	3
Total	2.5	7.5	10

So the %alcohol of total = 2.5/10 = 25%