Will this diagramming eventually become something we can do in our head with less writing?

@Kaitlyn, Definitely. Writing it out in the explanations is done only for practice purposes, on a real test you would likely be able to do most of the inferences in your head and only use diagrams for formal logic questions that are harder to visualize otherwise. It is perfectly normal for these questions to take time when you are just starting to study. For example, for this question as I read it I would mentally make a note that the pattern of reasoning here is IF A THEN B, IF ~B THEN ~A. As you go through the answer choices, you immediately notice that all of them except for the right one introduce a third variable. IF A THEN B, IF ~B THEN C or a variation thereof. (C) is the only one that uses the same two variables for both premises. Using abstract variables (A, B, C) or (P,Q,R) rather than content-specific variables (e.g, MC for maintain spending) is also generally easier when diagramming as we are only interested in the logical structure rather than the substance of the argument. Good luck with your studies.

Sounds great. Thanks so much!

@irina, This is very helpful. I had the same question as well. Which questions (formal logic) do you suggest we we always diagram rather than infer?