#23 - Local, Could Be True

[Dave Killoran]

Complete Question Explanation
(The complete setup for this game can be found here: lsat/viewtopic.php?t=17223)

The correct answer choice is (A)

The chairperson in the second year must be someone who can serve in the second year and someone who had to serve in the first year, so to answer this question think about who must serve in year 1 and who could still serve in year 2. If I serves as the chairperson in the first year, then I cannot serve in the second year. Further, since V cannot serve with I, then V cannot serve the first year and thus cannot be the chairperson in the second year (eliminating answer choice (D)). However V must serve the second year since I is absent, so G cannot serve in the second year (eliminating answer choice (B)). If Z is absent in the first year then the other two scientists—Y and Z—must be present, meaning that H cannot serve the first year (eliminating answer choice (C)). Finally, since G and I both cannot serve in the second year, then the other two lawmakers—F and H—must both serve in year 2, meaning that Y cannot serve in the second year (eliminating answer choice (E)). That leaves only answer choice (A), the correct answer choice.

[lsat_novice]

I'm struggling to understand the answer to Question 23.
Based on my diagrams it seems like Feld, Gibson, OR Young could be the chairperson in the second year.

Does anyone understand this problem?
Thanks in advance!

[Adam Tyson]

Let's see if I can shed a little light on it for you!

If I is the chairperson in the first year, that tells you a few things. Let's see what that first year panel could look like:

I is in, so V is out, per the last rule.

Since V is out, Y and Z must be in, because we need two scientists.

With Y in, H has to be out. That means the other lawmaker, besides I, is either F or G. Our first year panel is, therefore:

I (chair), Y, Z, and F/G

Now, the chair in the second year has to be one of those people, but I cannot be included in the second year, so our options are, for the moment, Y, Z, F and G. We can eliminate answers C and D.

Now take a look at the second year, and see what rules apply. I is out, and per the last rule that means V is in.

V in knocks G out, per the first rule! That eliminates answer B.

Of our lawmakers, we now know that I and G are out, so they two lawmakers on the panel in the second year must be F and H.

H in knocks Y out, per the second rule! That eliminates answer E. We are now left with only answer A, which must be the correct answer. Z could also have been the chairperson, but Z wasn't available as an answer choice. The second year panel would have to be made up of H, F, V, and Z, and either F or Z could be the chair.

The key here is to use ALL the rules to get there. It's easy to see that F or G and Y served in the first year and thus have met one requirement for being the chair in year 2, but we still have to look at the numbers (two from each group) and the restrictions on who can and cannot be together and who must or must not be included in order to see what all the possibilities are. Go further to see how each inference impacts additional inferences!

[lsat_novice]

Thanks for the thorough explanation!