Data Sufficiency

OA is C

the answer is C.
Would you please tell me where you bought this GMAT practice.

Answer should be C - Here's why https://www.beatthegmat.com/weighted-average-t28451.html

Whats the source?

Abdulla wrote:OA is C

Here's another thread in which I discuss using a number line to understand weighted averages:

https://www.beatthegmat.com/what-fractio ... 11500.html

Just want to confirm that the answer is 66% based on the weighted average method. 1 and 2 are not sufficient so if we combine:

G-----------------Avg----------------U
40 20

U/G = 40/20 = 4/2 = 4/6 or 66%

adamsmith2009 wrote:Just want to confirm that the answer is 66% based on the weighted average method. 1 and 2 are not sufficient so if we combine:

G-----------------Avg----------------U
40 20

U/G = 40/20 = 4/2 = 4/6 or 66%

No, that's backwards.

The overall average is closer to the undergraduates, so the undergrads must carry more weight.

Well, it may be right if you're answering the wrong question

You've set up the number line and equations properly, but the question is what percent are graduate students, so the answer is 1/3, not 2/3.

Ahh - I see. I had the undergraduate ratio and not the graduate. Thanks Stuart.