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This is a Logic Games question from the December 2003 exam.
We'll skip the first question and go to the more challenging second one. As usual, we'll use a table with symbols as our diagram. It will look like this:
S | T | U
x | x | x
S, T, and U stand for the plays, and the x's will be replaced by the first letters of the names of the people who reviewed those plays. We need to find an arrangement of symbols in the table that will work with the rules. Then, we'll compare the choices in the question to our correct diagram. Any choice that doesn't agree with our diagram doesn't have to be true, so we can eliminate it.
Some of the choices we make will be arbitrary, and that's fine. They just need to fit the rules. Let's have K review T, M review T and U ,and L review U only, since the first rule says M must review more plays than the others do.
S | T | U
| KM | ML
We need to add O to T, according to the rules:
S | T | U
| KMO | ML
This also gives us the one pair, K and O, that review the exact same plays as each other. Now, let's put J as S's reviewer:
S | T | U
J | KMO | ML
Now, the choices:
A) Not true in our diagram, so it's wrong.
B) Could be.
C) Could be.
D) Same as A.
E) Same as A.
Now, we need to alter our diagram to eliminate another choice. Let's test choice C by putting O in as the reviewer of S and T, and put L in as T's reviewer, which will violate C (L and K will be our pair that is always together):
S | T | U
JO | KMOL| M
That fits the rules and eliminates C, so we now know B is correct.
Remember:
This is an unusually difficult game. However, by making a diagram of a table and then altering as needed is effective. As you practice, you'll be able to do long questions with ease.
Feel free to post any questions in the comments.
Thanks for the new question =)
ReplyDeleteFor a "must be true" question, throwing stuff down arbitrarily seems like a risky strategy. But with two more days of practice, I'll have some chances to try it out. After all, your arbitrary choices immediately cut out a few of the options.
ReplyDeleteYou are incorrect. The arbitrary choices yield a diagram that fits the rules. Any choice that must be true must be true in that diagram. So, no risk. Your statement would be correct for a "could be true," absolutely, but not a "must be true." If it must be true, *every* correct diagram must agree with it.
ReplyDeleteYeah, it appears as though just one 'arbitrary' diagram can immediately get rid of a few options. And I'm starting to think that working out each possibility or trying to compare each possibility with a rule would take much longer. This works, and may very well be the most efficient method.
ReplyDeleteHi, a very helpful site indeed. I'm studying for the dec. exam, and I was going through your archives. I noticed on the early logical reasoning questions, you are a major proponent of pre-phrasing. I like this idea as well in, because I need any and every tip to speed up the process, as I seem to be doing well without time constraints. Anyhow, with the recommended pre-phrasing, I noticed on your other questions, you say we are only going through the other wrong answer choices because this is practice. Does that imply that on the actual test you would advise us to go to the next question immediately after spotting our pre-phrased answer or do you advise taking some more time to scan the other answers? I really think pre-phrasing, finding the answer, and not even looking at the others would save a lot of time for a guy like me who needs to make up a lot of time to get all the questions done. please let me know what you think. thank you very much.
ReplyDeleteI guess it depends on how you're doing on time. If you have time, scan the other others, sure. If you're running out, I'd just move onto the next one without even looking at the others. But with practice, your speed should improve, allowing you to scan the other choices.
ReplyDeleteMost of the must be true questions have a trick to them that's pretty simple. Because of this, you can usually just scan the choices and see if you can eliminate them in your head.
ReplyDeleteIn this case, you see that every choice concerns relative numbers of plays reviewed. Therefore you need to conclude something relating to this. The only thing you can conclude is that M reviews 2 plays, because he (she?) reviews more than one, and J/M never review the same play. Therefore, J can only review one play (bc there are only 3 total). 1<2, so M reviews more plays than J.
This process takes about 20 seconds, which I think is easier than writing out an arbitrary diagram, the helpfulness of which isn't guaranteed.
This is my response to the last comment. I think, it IS the most difficult part - to be able to isolate the "most restricted letter", which is "M", and from there draw the conclusion that M appears twice (bc it can't appear once, neither three times, or else "J" falls out of the picture completely). I guess, diagramming is the first thing on the mind to do. But, as usually, "MUST BE TRUE" are inference questions requiring no diagram. And mostly, the answer lies in the most restricted element (letter, person, whoever) of the game. So, attention should be drawn there right away. If not, then diagamming is the next solution. Although, in lots of situations it might take plenty of time and not always to avail.
ReplyDeleteTHANK YOU FOR POSTING QUESTIONS! THIS IS A GREAT WEB-SITE!
Umm, I think if you just do a diagram using J/K/L/M/O as your columns instead of thed plays, s/t/u. It's a lot easier. Since M has more than K or L, it has to have at least 2, and since it can't share any with J, it can't have 3. Forcing M to have exactly two plays. J, in turn is forced to have one.
ReplyDeleteWhen I did my diagram this way, the answer was pretty obvious. It jumped out at me when I scanned the answers.
I just think when one set of entities is more concrete, you should use that set to make you columns. For example, since we know from the set up that every student has to review at least one play, they seem more rooted. The rules later will force us to have at least one of each play, but it seems for circumstantial.
Thanks for the game!
Hi you guys make good points!!!
ReplyDeletedoes any one know what is "pre-phrasing" ?? I am not exactly not sure what this term means?
Pre-phrasing is forming your own answer and then looking for it in the answer choices.
ReplyDelete