This is an explanation of the fourth logic game from Section III of LSAT Preptest 77, the December 2015 LSAT.

Three volunteers out of five people will be assigned to three community committees (X, Y, Z). The volunteers are Haddad, Joslin, Kwon, Molina, and Nash (H, J, K, M, N). Each of the volunteers will have one of three positions – leader, secretary, or treasurer.

### Game Setup

This one of the most “classic” games I’ve seen in recent years. If you approach it using only the rules, it’s extremely difficult. However, if you make a few upfront deductions, it’s very easy. This kind of game used to be very, very common. Now they’re rare. The first three games from this test are more typical: two rules based games, and a “weird” game.

However, it’s useful to practice the old games because they’ll let you breeze through classic games like this. Let’s look at how to set up the game.

First, and this comes from experience, it’s most useful to set this game up vertically. There are many past games that follow this format. You’ll see why this is best as we add deductions:

Next, don’t just go through the rules in order. Start with the *easiest, *clearest rules, and draw them directly on the diagram. Rule 1 says that Nash must be in leadership. We can draw this on the diagram by putting a ~~N~~ below S and T:

Next, the fourth rule is clearest. It says that Joslin is the secretary for Y, but can’t be on committee X or Z:

Next, rule 3 places Kwon somewhere in Y, and says that Kwon can’t be in Z:

I’ve drawn K to the right of Y to indicate that they must go somewhere there. I’m saving the spots on the left for people who *can’t *go on a committee.

The final rule, rule 2, is that Molina can only be assigned to one committee. At first glance, it doesn’t seem like we can draw this on the diagram. But let’s stop and think about all the rules.

It’s always important to count numbers on logic games. Look particularly at the most restricted places. There are only *five* volunteers on this game, and each committee needs *three *volunteers.

Z is the most restricted committee: K and J can’t go there. That knocks 2/5 volunteers off the committee, so *all the other three *volunteers have to go to Z:

N, of course, goes in leadership. M and H are interchangeable between the other two roles. And we’re not done yet. Remember how rule 3 said that M can only go in one group? Since M is in Z, that means M can’t go in X or Y:

Now both M and J can’t go in X. This means that the other three all have to go in X: N, K and H

Once again, N is in leadership, H and K are interchangeable between the other two spaces. We’re more or less done, all that’s left is to note who goes in Y. Along with J, it will be K and one of N/H:

J is already in Y. K *has *to go in Y as well. M can’t, so the other space will be N or H. If N goes, obviously N goes in L. If H goes, then H and K can go in either spot.

So almost everything is determined in this game.

—————

**Repeating Games**

I’ve written elsewhere about the benefits of repeating games, to solidify your intuition for deductions. Note that the purpose of repeating games is to *prove *the answers right, so it doesn’t matter if you remember the right answer.

I repeated this game about three days after I first saw it, by which time I had forgotten the answers. I’ve written how long it took me on the second attempt. That time, or a couple minutes above it, is roughly the standard you should be aspiring to – a lot of people take 8-9 minutes on a repeat attempt, get everything right, and pat themselves on the back. But that’s too slow. The faster you go when repeating, the faster you’ll learn to go the first time you see a game.

(I say “a couple minutes above” my time because, after years of teaching the LSAT, I’m really, really fast. You should be almost as fast as me, but you don’t exactly need to match my pace to score -0.)

**Time on second attempt: **5:01

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S says

Hi Graeme,

When you make this inference:

“Z is the most restricted committee: K and J can’t go there. That knocks 2/5 volunteers off the committee, so all the other three volunteers have to go to Z:”

I actually interpreted it as it’s not necessarily the case that ALL other three volunteers have to go to Z. Couldn’t it just be two of them, repeated? Or one of them, repeated? After all there are 9 spots and only 5 volunteers.

sylvia says

Hi Graeme, thanks for the explanation. What confused me is the wording “with each volunteer on a committee holding exactly one of three positions – leader, secretary, or treasurer”. Isn’t it true that this should be interpreted that it is not necessary for all three positions to be in the committee, i.e., there can be one leader and two secretaries? Nowhere in the question provides that each volunteer should hold one of three positions, three positions being all different or that each committed must have all three positions. Please help. Thanks!

TutorLucas (LSAT Hacks) says

On the LSAT we’re expected to make common sense assumptions. Although the question doesn’t specify that each committee must have exactly one leader, exactly one secretary, and exactly one treasurer, it’s safe to assume that each committee has exactly one of each role. They’re committees after all — having two-three leaders with no one to lead wouldn’t make a lot of sense.