sdlife wrote:

Bunuel,

VeritasPrepKarishmaI understand this is a weighted averages problem. But I am having a hard time understanding how we take percentages as the "average" for a group. To me 'averages' are an absolute number (not %). Could you please explain what am I missing here?

BTW, Can you also check if my weighted average solution for this problem is correct?

If we apply the weighted average concept here for choice A:

AvgM = 36%, AvgW = 50%. Total Average (AvgT) = 42%. So since we know all three averages, we can calculate the ratio of the weights using the formula:

Wm/Ww = AvgW - AvgT/AvgT - AvgM. This will give us the ratio of M/W and since we have total of all surveyed, we can find number of women.

I think I am confused as to why we are taking these percentages as Average for that group.

Yes, it is and your method is correct.

Percentages are just a way of expressing concentration.

So you have two groups made of two ingredients - "people who consider engaging in research essential" and "people who don't consider it essential"

So we work with the percentage of "people who consider engaging in research essential". It is the same as working with the concentration of one of the ingredients.

_________________

Karishma

Veritas Prep GMAT Instructor

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