Received a PM asking me to respond.

Yes, inference questions can be tricky. The key is knowing what they want from you. If you understand what they want, then it's easier (though not necessarily easy!) to figure out the right answer.

The biggest mistake people make on inference questions is thinking that "infer" means what it means in the real world. For example, if I tell you that I think cats make the best pets, you might infer in the real world that: I like animals in general; I like pets in general; I have a cat; I have other kinds of pets; I like other kinds of cats (lions, etc); if we went to a pet store and I bought a pet, that pet would be a cat; if I came over to your house and saw your cat, I would pet it and play with it; etc. But not one of those would be acceptable as a GMAT inference answer! Instead, an acceptable answer might be something like: I don't think dogs make the best pets; at least one other type of pet is better than dogs; some other types of animals besides cats can act as pets; etc.

The "real world" inferences aren't acceptable because you could argue with any one of them. I might like only cats and no other animals or pets. I might like only house cats and no other kinds of cats. I might be allergic to cats and therefore don't have a cat, wouldn't choose a cat if I were at a pet store, and wouldn't pet or play with yours. (By the way, large parts of this scenario are true! I do think cats make the best pets - at least, they'd be the best for me - and yet I am actually allergic to them.)

The "GMAT inference" examples are acceptable because you can't argue with them. If I think cats are the best, then by definition, I don't think some other type of pet is best, and any other type of pet is not as good as cats. By the same token, if I think cats are the best, then I must accept that there are other categories of pets - "best" is a comparison, so I must be comparing to other types.

So, first, it's important to know this distinction: you do NOT want to try to infer the way you would in the real world. Rather, the correct GMAT inference is going to be something you can't argue with. It's going to be something you can prove to be true based upon some information that's in the passage. (Note: that last part is critical; the evidence MUST be in the passage.)

Here's an article that talks specifically about how to analyze an RC inference question:
https://www.beatthegmat.com/mba/2010/02/ ... e-question

The article will give you a more in-depth discussion of this principle.