Logic

I wanna be in that class...Omg. I'm so jealous.



That's a horrible example. In no way does it relate b and c, beside saying they're both less than a. Of course you couldn't expect b > c.

Those are two examples, they aren't interchangeable even though variably related. I wasn't trying to make the connection anyway, the point was to demonstrate 2 kinds of definitions I hold for logic:
1/ Ultimate truth of life
2/ Sequential reasoning

Logic is different for everyone though. I pose this scenario:

You turn into an alley on a street (for some reason lol), no one else is around. You see a man with a gun pointing his gun to another man on the floor who is unable to defend himself in the slightest. You have a knife in your hand for some reason, and could safely get behind the man with the gun and stab him.

Let's put three people, who are labeled A, B, and C into this scenario as the person with the knife, and the man with the gun/defenseless man remain constant.

Person A: "I'll stab the gunman in the heart, essentially killing him. It's the right this to do because I'm saving another man who is defenseless."

Person B: "I'll stab the gunman in the arm so he can't use the gun, but I won't kill him because it's immoral to kill."

Person C: "I'm not doing anything because I don't know the situation, so I'm just gunna walk out of this alley and get some dunkin donuts until it's safe to go home."

"Logically" they all believe they are doing the "right" thing. It "makes sense to their brains."

But...? Which one is right? "Logically" there must be one correct solution, no?

Essentially, what is true and what one believes is true aren't... the same. To follow up on your example, even though I don't see how it relates to logic, each person's decision was derived based on their given conditions. If person A believes killing is the only way to stop killing, then logically, he will kill. Likewise, if person C believes a dunkin donut is more appealing than saving a man's life, he will naturally select the better choice between the two.
How each of they has arrived at their own beliefs is yet another process, most likely driven by logic as well (person A has had experience with people not giving up unless he deliberately overkills them, for example).