I had also wondered about how to tell from the LSAT questions how to gauge what is rhetorical and what is a sincere question. After doing some research I was provided these examples (the key being the implication of an obvious answer or to serve as a method of persuasion in an argument). For example:

"Sandy claims to be a world-renowned baker. But has she ever actually baked a cookie or does she just order them from Costco and place them on a fancy plate?"

This would imply a very specific answer (to my understanding), making it a rhetorical question. Versus the question below:

"The recent decline in the global frog population has scientists puzzled. What environmental factors could be causing such a widespread and rapid decrease in their numbers?"

This would be a sincere question, without implication of a specific answer. Ill have to keep looking for more specific LSAT excerpt examples but this was helpful for me.

Hello! My name is Sophia, I am 26, currently working at the Seattle U law school and a graduate from Gonzaga University in Psychology, Political Science, and Criminology. I am planning on the April test and would love a study buddy or chat with anyone who is in the same boat as a full-time worker and a (hopeful!) first ten law student!

@Pknoblo Hi Paulina! My name is Sophia, im 26 years old and also planning on taking the LSAT in the spring (April is the hope) and live in Seattle. A little nervous about this exam but really hoping to do well and excited for the opportunity!