Try Your Hand at the LSAT!

In My Humble Opinion
61

Question number four. The Larch.

This one actually doesn’t come from Barron’s, but from the Princeton Review online practice LSAT that I took a couple of days ago. And it’s an Analytical Reasoning question rather than Logical Reasoning. These are those logic games that people like to play, where it gives you a scenario (ex. “There are six people sitting around a table.”) and the facts and conditions of that scenario (“John is not sitting next to Betty. Fran is married to Mr. Merkin. Two of the men are wearing goatees, and one of them is not Frank.”). Then you have to fill in the blanks as much as possible, while each question revises the conditions a little and asks how the picture is further filled in.

There are usually about six questions for a given scenario. I’m only going to give you a single question and a scenario–it’s the question that really bugged me when I took the test. And here’s the caveat: I’m not giving you the answer Princeton Review gave. It’s irrelevant, because as far as I can see the added condition in this scenario makes the original scenario impossible. And you can’t have that. So I just want the gamespeople amongst us to tell me whether in fact this puzzle can be solved. No logic needed.

Here’s the question. Rather, it’s a paraphrase of mine, since the test was online, but the conditions are accurate:
There are six electrical towers, A, B, C, D, E, and F. These towers are arranged in two parallel rows of three, with A, B, and C in row one, and D, E, and F in row two. Like this:

A D
B E
C F

There is a single line of trenches connecting all six towers. Here are the conditions for how the trench line has been constructed:

Every tower is connected by a trench to at least one other tower. No tower is connected to more than two other towers by a trench–that is, no tower is the nexus for more than two trenches. Towers may be connected diagonally, but not by way of a curved trench. No two trenches may intersect. A trench connects towers A and E. A trench connects towers B and C.

Got that? Those are the initial conditions. Now the question I have trouble with adds the following factor to the equation:

No towers can be connected to the tower directly across (to the left or right) from them.

Now, my observation is this. There is no way you can satisfy the previous conditions without connecting two towers which are across from one another. I’d like someone else to test that.

The question actually said, “If no tower can be connected to the tower directly across from it, which of the following MUST be true?” It listed five choices, three of which were obviously wrong. The remaining two were: C) F is connected to exactly two other towers, and D) E is connected to F.

As far as I can see here, even if you could meet the above condition, these two choices are mutually inclusive. If no towers connect across from one another, and F is connected to exactly two towers, then it must be connected to E. Thus my confusion.

I said I wasn’t going to show the answer that the Review gave, because it doesn’t matter. And it doesn’t. But to those of you who need to know, I’m pretty sure they chose D.

So assist me here, kind folk: is there any way to meet the condition of the question while staying true to the initial conditions of the scenario? If there is, I can’t find it. And if there isn’t, it ain’t just Barron’s that’s wacky. And that’s a frightening thought.

62

Gadarene, draw the line D-E-A-F-B-C.
I think that fits the rules.

63

This kind of question gives me a headache. I think I’ll pass (a concept you will have to master in law school).

Just wanted to glory in the fact that there is another idiot out there who regularly misidentifies anonymous trees as larches, drawing confused looks from others.

64

2nd Law gets the cookie!

65

Wow…and so it does. It never even crossed my mind that one could connect A and F, honestly; the other questions (this was the last of the set) and the initial conditions all utilized only bisecting diagonals (southwest, rather than south-southwest). Damn. Thanks, 2nd Law! By showing me that I was wrong, you’ve ironically given me more confidence in taking the test!

66

My apologies in advance for the length of this post. Also, this is written more with the though of getting points on an LSAT rather than doing logic puzzles for fun. I would have sent it directly, but in the chance that there are other lurkers out there interested in the thread for LSAT purposes, I am posting it here. (And please forgive my use of periods in the bits of diagrams. Couldn’t figure out how to get spaces to work.)

In must be true logic question, you know that buried somewhere in the additional rules of the question there is a forced consequence. BEFORE you move on to the answer choices, put the new rule into the game. In this type of a question (must be trues) you MUST NOT LOOK AT THE ANSWER CHOICES FIRST. Why? Because in most must be trues (and of course there is the rare exception) one or two choices will easily be bunk, two or three might look good, but there is, of course, only one answer. Why waste time debunking the others when you can zero in on the one that will get you a point? As soon as you are given a new rule go directly to the game setup, plug it in and keep track of what ‘must be true’. Then, and only then, hit the answer choices. In this case you are NOT evaluating the answer choices for fitness, you are merely scanning them for information you already have.

As for the problem, look at what you have.

A D
B E
C F

After you read the initial rules, you have

A…D
…
…
B…E
|
C…F

From the initial rules, you know that one line must connect all of the towers. You now have to work with the new condition that no tower can go straight across. Start with tower D. Because of the new rule, you cannot connect to A, so the following must be true

A…D
…|…D must connect with E
…|
B…E
|
C…F

File that new fact away in your mind. (Depending on your personality you may want to quickly glance at the answer choice to see if it stands out. Each fraction of a second really does count. In this case it does not look like it will pay off, but it might in others. You have to decide which is best for you in terms of getting the most points on the test and consider practicing that strategy. )
Where to move next? Go to the next tower that has no connections - F. (there are many possible other places to go. In scenarios where you are trying to restrict your outcomes (i.e. find definite situations) go to the one that appears least limited. Again, this is a general rule of thumb, it will be up to you to work it into your overall strategy.)

Because of your initial set up, you know F cannot connect to E. This would violate the ‘no more than two’ rule. It can’t connect to C because of the new rule. It can only connect to A or B. If it connects to A, than to keep one continuous line, it must connect with B. If it connects with B first, then again, to keep on continuous line, it must connect with A. In other words, you now know that

F * must connect with both A and B. *

You now have the entire game mapped out, and you have two statements that must be true in your hand (of course, you wrote these down on your scratch work as you came across them!) Now that you have the answer in front of you, attack the answer choices and find the one that matches. Screw process of elimination on games like this (unless, of course, if you get into a jam and must guess) you have the answer. This is why it is IMPERATIVE that you methodically work through the new information that you are given keeping track of the consequences.
MUST BE TRUES could be labeled ‘Find the new deduction’. Unless it is an unusually easy question, there will be a new deduction that will become apparent as you work out the set of rules (or more typically, add the new condition/rule to the previous set). Steadily work through the game until you find these new deductions. Move on to the answer choices and find it there. Take the point. Move on.
If you are relatively happy with the score range you are getting now, you should be concentrating on honing strategies for particular LSAT segments and questions. Work on making these strategies second nature, so on test day you are confident with what is in your mental toolbox. For games, work on standardizing your diagrams. Work on questions you have to ask yourself as you draw them. (I.e. can I make a contrapositive out of this rule? What rules can I combine? What blocks form when I apply this rule…) Work on the process of solving a game rather than the solution to a particular game. The lesson you should learn from a game is not how to solve it, but how to get to the solution, and how to apply the method you used to other problems on the test.

Sorry for being so longwinded about this one, but it is the first time I’ve really had a chance to post to this thread and I wanted to be a bit clear. Don’t worry about answers to individual questions - concentrate on the skills needed to get to the solution. Study to the test, not to the problem

67

Let me say that I although I agree somewhat with rhythmdvl’s approach to solving these analytical logic problems, it may not work for everybody. Some people will have an easier time plugging in answers since it is assumed only one works (that largely depends on how well-defined the conditions are).

That said, when I read through the question and the condition I immediately stopped to see if it could be answered before I read gadarene’s post any further. And the answer I came up with was : E-A-B-C-D-F

Unless I’m missing some conditions, there’s several ways to solve the trench pattern, although I haven’t figured out any necessary consequences.

The problem I see with rhythmdvl’s analysis (of this particular question, that is) is that it doesn’t follow that at the first step D must connect to E (it appears it could connect with up to two of B, C, E, or F at that point).

Since my answer doesn’t fit with the choices, am I doing something wrong or should it have been one that wasn’t given?

68

Okay, I suddenly saw what I was doing wrong … I misinterpreted ‘curved’ path to mean one with curvature, as opposed to one that has bends in it. So all trenches dug from tower to tower have to be perfectly straight, to put it another way. Then the answer given is the only one.

Sorry about that.

69

PanamaJack is right - no one method will work for all people. I alluded to checking answers in my post ("Depending on your personality you may want to quickly glance…) but in the end generally advise against it. Also notice that I didn’t suggest looking at the answers until after you have at least one possibility.

A bit more on this - when I say don’t go to the answer choices yet, I mean don’t do it in this very particular case. Don’t use process of elimination on must be true types of questions. This is part of building a strategy that I talked about near the end of the post. Could be trues, a different type of question in logic games that do lend themselves to elimination. A different mental tool for a different type of problem. Concentrate on strategies (or methods, or processes, if you prefer) for solving types of questions rather than specific questions.

Think about test day. You hit a ‘must be true’ (MBT) question. What happens now? First off, did they give you a new rule (as they did in your example) ? If not, than you know that there is a deduction that can be made from the rules in the initial game. Did you find any when you set up? If so, go to the answer choices and find it there. If not, go back to the setup and in an orderly fashion go through the rules again (combine them, make contrapositives, etc…) until you find a hidden deduction. Whatever it is, that, by definition, must be true. As that is the case, find it in the answer choices and voila, you got a point. Still don’t see your deduction in the answer choices? Than you know you didn’t find them all - look for other deductions - second or third level deductions. Of course, if you can’t find a deduction you should use the answer choices as an assist, but this can be very time intensive, and you may want to consider moving on to another game and/or question.

If they did give you another rule, put it into the game, find out what it means, see how it affects the game and find the hidden deduction. Once you are armed with information, THEN AND ONLY THEN does it make sense to hit the answer choices. The cumulative time difference between finding the deduction (even though it may take a bit of time) and trying out answer choices in this question type (which will, on average, take much longer) can make a huge difference. (Remember, I am talking about a section-wide strategy. You may see several MBTs on test day).

Another danger to plugging answers into a MBT question, is that if an answer works, it very well could be true, but is not necessarily true. In this example the extra rule completed the game, but you will definitely have games in which there are still other possibilities. In those instances, you will have more than one answer choice that can be true. That was time spent not getting a point on the test. Find the deduction first, get the point, move on.

The things I am talking about here (and other strategies for answering ‘can be true’, ‘cannot be true’, ‘must be false’ and so on) is what you should be concentrating on for test day. Learn and practice different strategies for different question types. Learn and practice different strategies for finding deductions. Learn strategies for following logic. For finding an author’s point of view. For strengthening or weakening an argument. All strategies to apply on test day. Study to the test, not to the problem

70

Are we done doing problems? I don’t know about the rest of you but I was getting a masochistic thrill from being wrong.

71

Oh, I can keep going…I’ve got a few more yet. :smiley: Want another?

Oh, and Rhythmdvl, thanks for the excellent advice. Your posts make really good reading.

72

Thanks. Remember, just as Panamajack pointed out, different things work for different people, so adapt what I, others here, the books, etc. tell you. Practice making them your own so that you’ll get the most points you can on test day. Keep throwing q’s here if you wish, I’ll pipe in when I can with what strategies I can. The q’s could be fun for a lot of dopers, maybe something in it for other test takers.

By the way, where are you applying? I’m sitting on about fifteen or so applications, trying to whittle the final list down. Maybe our paths will cross in a torts? If so, and if I helped you get as much as half a point, I think you’ll have to buy me a beer :slight_smile:

And to the mods – I’m being very careful not to repeat any copyrighted information verbatim – that is, not stock phrases, etc. I also don’t think I could give enough away in this forum to raise any issues (it is normally a ten week class). But, as a guest on your boards, please let me know if you think I’ve crossed or am about to cross any lines. Thanks.
Rhythm

73

Gadarene,

Basically, Barrons LSAT book more or less sucks. It isn’t even good for throwing at people when they’re making too much noise in the hallway, it just kind of flops about 2 feet in front of you.

I used it when I was getting ready for the test, found the questions to be stupid, and the reasoning to be flat out wrong. Luckily for me, I’m incredibly arrogant, and automatically assumed that it was a problem with them, not me.

The one thing it does do is get you used to the style of the questions for all three parts, and answering however many questions it is in however much time it is.

If you understand how you should answer the questions, what types of things you should consider in the reasoning section, the style of the articles in the comprehension section, and doing logic problems (for that, use the magazines you find at the checkout aisle rather than the review questions - they’re need repeat customers, so the problems are better written, better edited, and they can’t afford to make idiot mistakes), you’ll be fine.

-amarinth

74

No problem Gadarene.

The suggestions above are good ones. My suggestions towards taking the test are practice, practice, practice. Take as many practice tests under time pressure/test conditions as you can stand up to two days before the test. The day before the test, relax.
And when you go to actually take the test, remain calm! When I went to take the LSAT, my attitude was “I wonder how well I’ll do at this. If I do well, maybe I’ll go to law school. If not, I can go do something else.” Most of the people there were college seniors who thought if they did badly they might as well kill themselves, and the tension was so thick you could cut it with a knife. More than one of the poeple in my testing room had to leave because they became physically ill. There’s no way you can perform well on the test if you’re that tense.
Good luck!