I have watched the solutions video a few times now and still don’t quite understand that B is bigger because angle z must be larger than 2y. I know z>y do to the relationship, but I don’t see how that tells us info about 2y.

You can’t do this rigorously without geometric constructions, trig, calc, etc. You may just skip the question.

Last I checked, the GRE does not use trig or calc…so it must be possible.

Yeah, and that’s why i said you can’t do this question without those tools. You can also do this question with geometry, but that kind of geometry is beyond what you see on the GRE.

Maybe it is a poor question, but this is on the Gregmat website so I would think it must be possible.

The video can be found here by the way: Quant Quizzes By Difficulty - GregMat

It is of course possible to do the problem like i mentioned prior, but just not with the tools you have available for the GRE.

For example, geometric constructions like the one i made on the below image solves your problem immediately, but again I don’t think this is part of the GRE.

You can trust me lol , and safely skip the question unless you happen to be interested in actually solving this question.

I’d like to solve the question with the tools you would learn from Prepswift and gregmat. Did you watch the solution? I am looking for someone to explain to me that part.

It’s a bad question, please skip it for now.

Can you check this post where Greg talks about it?

https://www.reddit.com/r/GRE/comments/1d03zk9/gregmat_mini_exam_19_question_12/

At the risk of repeating myself, it is not possible to do it with skills you pick up from the GRE. You can make constructions which exploit similar triangles and the like, but the act of making such constructions is not really tested.

Have you watched/read (the thread ganesh linked) the solution

Yes, the solution is wrong or well the assumption is not warranted/ without proof . I saw that Greg did:

- C is right → Proved
- B is right → Proved
- C = 60 degrees and A = 30 → Showed a contradiction

But these 3 cases don’t say anything about the generalized case where we’re dealing with any triangle ABC with AB = 2BC. Therefore, this is not any better than just guessing the answer.

cylverixxx is correct; I remember that we removed this question from another quiz for this reason as I did not agree that “pattern recognition” was rigorous enough.