Daily Drills 19 - Section 19 - Question 3

P: A → CP: C → BP: not BC: ?

Egurlie55 December 5, 2022

I don’t understand

I’m not sure how to get these types of questions correct. When i finish the drill questions, sometimes I get these right but most of the time I’m wrong. How do I understand the process of the formula that’s used in these types of questions. How do I start? Is there some sort of pattern to follow?

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Emil-Kunkin December 12, 2022

Hi, I would always try to link together premises. Here we can start by connecting the first two premises to give us
If A then B, and it's contrapositive if not B then Not A. With this new rule, we can see that I'd B did not happen, A did not either. So, we can then combine this with our final premise to prove that A did not happen. This act of trying to link ideas together is a key skill.

Egurlie55 December 25, 2022

I don't even know what the premises would be by looking at the equation. I literally don't know where to start in terms of "link together premises".
Your explanation helped a little, but it's not giving me the meat and potatoes I need to start. Can you provide a more detailed example referencing the question ID#20242?