Logic Game Technique with Global Questions

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

Logic Game Technique with Global Questions

Postby secretad » Tue Apr 19, 2011 9:53 pm

By global I mean "What must be true, what cannot be true...etc." It does not involve "if X is 3rd, what must be true." I am not discussing local conditions, but globally in the game.

Which technique do you feel is better?

1) Do if questions first to have hypotheticals and rule out many choices on must be true questions.

2) Go after must be true questions first, although they may be more time consuming if you did not make the inference upon the set up, they would be extra useful as they act as another rule or constraint.


I tend to answer the questions in order and if nothing stood out at me as a must be true, I move on to the other questions with the confidence that future hypotheticals will rule out many incorrect answers to help me in obtaining a correct answer.

Your thoughts? Especially people with 170+

Thats my goal in life right now and I am so close.

dakatz
Posts: 2460
Joined: Sat Mar 29, 2008 4:19 pm

Re: Logic Game Technique with Global Questions

Postby dakatz » Tue Apr 19, 2011 9:58 pm

secretad wrote:By global I mean "What must be true, what cannot be true...etc." It does not involve "if X is 3rd, what must be true." I am not discussing local conditions, but globally in the game.

Which technique do you feel is better?

1) Do if questions first to have hypotheticals and rule out many choices on must be true questions.

2) Go after must be true questions first, although they may be more time consuming if you did not make the inference upon the set up, they would be extra useful as they act as another rule or constraint.


I tend to answer the questions in order and if nothing stood out at me as a must be true, I move on to the other questions with the confidence that future hypotheticals will rule out many incorrect answers to help me in obtaining a correct answer.

Your thoughts? Especially people with 170+

Thats my goal in life right now and I am so close.


For "must be true" questions, I like to work backwards by process of elimination. Think about it this way:

Ex. You are trying to figure out which one "must be true" and the first choice is "A goes in spot 1". So you put A in spot one, and voila, the setup works. But what exactly do you know at that point? All you know for sure is that A COULD go in spot 1, not that it MUST go there. The only way to prove if something MUST be true is to try and disprove it (which all relates back to my theory of why the right answer on the LSAT is right: because its the only answer you can't prove wrong). So take each "must be true" answer choice, and do the OPPOSITE of what the choice says. So if the answer choice is "B must be in group 2", put B in group 1. That will tell you immediately whether or not B MUST be in group 2. It sort of harkens back to the black swan example. If you want to prove whether or not every swan in the world is white, you don't keep looking for white swans. You try and find the black one so that your inquiry will actually end. Always apply this logic for "must be..." questions.

And one additional tip: Look to all your past hypotheticals that worked (btw, make sure to ALWAYS cross out the hypos that didn't work so you don't get yourself confused). Your hypos are the first things you want to look for when you attack a "must be..." question. If a choice is "B must be in spot 2", but you clearly have a working hypo with B in spot 1, then theres no need to consider that choice. You would be surprised how much time you can save by just knocking off answer choices based on the work from past questions.

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

Re: Logic Game Technique with Global Questions

Postby secretad » Tue Apr 19, 2011 11:55 pm

dakatz wrote:
For "must be true" questions, I like to work backwards by process of elimination. Think about it this way:

Ex. You are trying to figure out which one "must be true" and the first choice is "A goes in spot 1". So you put A in spot one, and voila, the setup works. But what exactly do you know at that point? All you know for sure is that A COULD go in spot 1, not that it MUST go there. The only way to prove if something MUST be true is to try and disprove it (which all relates back to my theory of why the right answer on the LSAT is right: because its the only answer you can't prove wrong). So take each "must be true" answer choice, and do the OPPOSITE of what the choice says. So if the answer choice is "B must be in group 2", put B in group 1. That will tell you immediately whether or not B MUST be in group 2. It sort of harkens back to the black swan example. If you want to prove whether or not every swan in the world is white, you don't keep looking for white swans. You try and find the black one so that your inquiry will actually end. Always apply this logic for "must be..." questions.

And one additional tip: Look to all your past hypotheticals that worked (btw, make sure to ALWAYS cross out the hypos that didn't work so you don't get yourself confused). Your hypos are the first things you want to look for when you attack a "must be..." question. If a choice is "B must be in spot 2", but you clearly have a working hypo with B in spot 1, then theres no need to consider that choice. You would be surprised how much time you can save by just knocking off answer choices based on the work from past questions.


I somewhat disagree what your first approach on must be true questions. The working backwards part.

If you are dealing with a wide list of slots, say 6 of them, and it says that B must be in slot 2, then you try to disprove it by placing B in slot 3 and it does not work? Then do you say forget this answer choice for now, it might be the one that has to be true because it just failed this first test, or do you say, well perhaps it could go in slot 4, 5, 6, or 7? Maybe it just couldn't go in slot 3 by chance.

dakatz
Posts: 2460
Joined: Sat Mar 29, 2008 4:19 pm

Re: Logic Game Technique with Global Questions

Postby dakatz » Wed Apr 20, 2011 12:08 am

I understand your concern but think if it this way: If the answer choice is "B must be in slot 2" and you actually out B in slot 2 and it works, you know that you must continue on and try to figure out every single hypo without overlooking any if you are to solve the problem that way. Anything less than that and you haven't proven that it MUST be true.

Compare this to my method. On each and every hypo you do, it may be the las one you need (since it only takes one working hypo to prove the answer choice wrong). Sure, there will be times when you will need to do multiple hypos to disprove it, but at least you have a chance of solving it quicky. You dot even he that chance by affirmatively Doug what the mud be true answer says.

And remember that you aren't doing the questions in a vacuum. You will almost never need to plug B into every single other spot. By using your initial diagram, the deductions you made, looking at your hypos, and using past answer choices and questions to your advantage, the world of possibilities is quite constrained.

And finally, this whole ting emphasizes the absolute importance of making FAST hypos. What you described above to me isn't at all a problem because I can do a hypo in seconds. You want to master the game from the beginning. Try and see the big picture and always remember the key rules. Making quick hypos is your best tool and, since it gives you a chance to see additional setups and make new deductions, it should be something you do as often as possible.

SanDiegoJake
Posts: 149
Joined: Mon Mar 07, 2011 3:17 pm

Re: Logic Game Technique with Global Questions

Postby SanDiegoJake » Thu Apr 21, 2011 6:44 pm

1 for sure. Do "if" questions first so you can organically create a bunch of hypos which you can use to rule out many answers on the later "must-be-true" questions.

However, in my experience, many "must be true" questions are solved by making deductions before I look at any of the questions.

Your idea that "I may have to test out too many other options" is correct in theory, but not in practice. On real tests, there aren't that many options that need to be tested. 3 or 4 tops.

Bottom line: Get more detailed in your deductions, and these must be true/false questions will seem easier.

By "more detailed", I mean things like using placeholders in your diagram. For instance, if there are 3 shelves, and the Vonnegut Novel cannot be on the shelf with either of the two comic books AND the two comic books cannot be on the same shelf as well, then you know that each shelf must hold one of each (either a comic book or the Vonnegut novel).

By the same token, if you're looking at an in/out game and you see a clue like "If x is in, y is out", then you know that at least one of the two must be out.




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