#3 - Global, Must Be True

[Adam Tyson]

I always hesitate before saying "always" about anything on this test, Lauren, but this comes pretty close! These types of questions, where every answer choice is a conditional claim and you have to see which one is valid, can be approached by asking yourself "is the alleged necessary condition really necessary in this case?" Sometimes, you might have an easy time eliminating one or more answer choices that way without having to draw them out, and you may even be able to zero in on one answer where you realize, perhaps based on the work you have already done up to that point, that yes, it IS really necessary when that local condition occurs, and you can confidently select that answer choice.

But sometimes things just won't be that clear, and you may have to make a choice to diagram multiple answer choices, or skip the question and return to it after you have gathered more info through answering other questions, or both. Do what you must, but don't be surprised if they take a little longer than some other questions, and don't let that discourage you from attacking them!

[izsake]

Hello!

I am not sure if I have been staring at this question for too long or just not enough sleep, but I can't seem to understand how to find the correct answer. My initial approach was to diagram each option to see whether or not it was possible - and somehow every single one seems to be true, work, and abide by the rules(??) Here is what I have come up with, I would incredibly appreciate if someone could help me figure out what I am doing wrong:

a) U, H, O, K&I, Z
b) H, U, O, K&I, Z
c) H, Z, U, K&I, O
d) H, K, O, U&I, Z
e) H, K, O, Z&I, U

[katehos]

Hi izsake!

The question you should be asking yourself is not whether each answer choice is possible, but rather, does each answer choice HAVE to be the case? Since this is a Must Be True question, it's not enough for the scenario in each answer choice to occur 1-99% of the time, it must occur 100% of the time. Instead, you should actually be trying to come up with counterexamples to the scenarios presented in the answer choice, as the four incorrect answers will be Not Necessarily True, while the one correct answer Must Be True.

For example, answer choice (A) says U on Monday H on Tuesday. So, let's try to come up with a way for U to have a session on Monday and H does NOT have a session on Tuesday. One way to do this would be to place the variables (from Monday to Friday, respectively) like this: U, O, K, H&I, Z. This scenario does not violate any of the rules of the game, but it does show that (A) is Not Necessarily True! Answer choice (D), however, must always be the case! There's no way to create a counterexample without violating a rule.

Pro-tip: on "5-if" questions like this where all five of the answer choices use the word "if", you can actually wait to do them until the end and see if you have any scenarios that you've created throughout the game where the sufficient condition in the answer is present but the necessary is not! These questions can require a huge amount of time, so being able to eliminate even a few answers this way can be instrumental in saving yourself time for future questions

I hope this helps!
Kate