PT32 Game 2...."Must at least select..."

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Easy-E
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PT32 Game 2...."Must at least select..."

Postby Easy-E » Fri Apr 15, 2011 2:45 pm

I'm a bit confused at the best way to attack #10. Since the question asks what is the least the organizer must select, is the best way to find the answer to see if you can make a valid selection set with using LESS than what the answer choice offers? For example, choice A is "one French novel and one French play". So, if I can make a working layout with no French novel and no French play, I know that answer is incorrect, and whichever choice I cannot create a working example for (using less than the given condition) is correct?

I hope that'd made sense. I'm not sure if I'm just missing out on my setup, since I really only drew out the rules, and no diagram or frames. I found the first three easy enough working it out mostly in my head (rule 4 really helped), but the last two kind of have me stuck.

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Re: PT32 Game 2...."Must at least select..."

Postby soj » Fri Apr 15, 2011 2:55 pm

Yes. This is the kind of question for which if you don't recognize the answer based on overall patterns and interactions between the rules (and this is very tough to do), you need to go through the process of elimination.

To prove (A) wrong, try to draw a sketch with one French novel but no French play, or vice versa (or neither). If you can produce even one such sketch, you can eliminate A. Be careful, not being able to produce a sketch that contains no FN and no FP is not grounds for selecting A as the answer. Not being able to produce a sketch that does not contain BOTH FN and FP (in other words, one or the other or neither) is grounds for selecting A as the answer. Again, notice that it's much easier to eliminate than to select. After all, it's hard for you to know if you've really exhausted all possibilities, or if you're unknowingly missing some of them.

You'll find that you can't prove (D) wrong because if you select only one French novel, you're forced to select at least two Russian novels (since at least 3 novels must be selected), but that violates Rule 3, which states that you must select at least as many French novels as Russian novels (so 1 FN and 2 RN is now allowed).

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Re: PT32 Game 2...."Must at least select..."

Postby Easy-E » Fri Apr 15, 2011 4:13 pm

soj wrote:Yes. This is the kind of question for which if you don't recognize the answer based on overall patterns and interactions between the rules (and this is very tough to do), you need to go through the process of elimination.

To prove (A) wrong, try to draw a sketch with one French novel but no French play, or vice versa (or neither). If you can produce even one such sketch, you can eliminate A. Be careful, not being able to produce a sketch that contains no FN and no FP is not grounds for selecting A as the answer. Not being able to produce a sketch that does not contain BOTH FN and FP (in other words, one or the other or neither) is grounds for selecting A as the answer. Again, notice that it's much easier to eliminate than to select. After all, it's hard for you to know if you've really exhausted all possibilities, or if you're unknowingly missing some of them.

You'll find that you can't prove (D) wrong because if you select only one French novel, you're forced to select at least two Russian novels (since at least 3 novels must be selected), but that violates Rule 3, which states that you must select at least as many French novels as Russian novels (so 1 FN and 2 RN is now allowed).



Hmm let me see if I follow. The whole "must select at least" is really throwing me off.

I can't make a valid sketch with no FN and no FP. This doesn't mean A is necessarily right, because it could still need require more than the given condition (1FN and 1FP). But, since I CAN make a working sketch using no French plays (ex. FN-FN-FN-RN-RP), I know that answer A is not the least requirements for a valid selection.

Heres where you lost me...

"Not being able to produce a sketch that does not contain BOTH FN and FP (in other words, one or the other or neither) is grounds for selecting A as the answer."

Can you rephrase this sentence somehow? I understand that if I had been unable to create a sketch without using both FN and FP, then A would have been correct, since every valid set up would need at least that. I don't understand the part in parentheses, I have read it a million times, and my brain is totally fried. What are you referring to when you say "one or the other or neither"?


Also, taking a glance at the answer choices, it seems obvious why D is the correct choice, since having any less than 2 French novels limits the number of Russian novels to 0 or 1, and you can't get to the 3-4 novels (or 5-6 total works).

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Re: PT32 Game 2...."Must at least select..."

Postby soj » Fri Apr 15, 2011 4:23 pm

Sorry, that was confusing, I admit.

The AC is "one FN and one FP."

If A were TCR, you would not be able to draw a sketch that contains no FN and no FP. However, being unable to draw a sketch that contains no FN and no FP doesn't necessarily mean A is TCR.

"A is TCR" is the sufficient statement.
"unable to draw a sketch that contains no FN and no FP" is the necessary statement.

Can you see why? Even if the necessary statement were true (and ignoring the fact that it's always easier to eliminate wrong ACs than to find TCR in a question like this), you might still be able to draw a sketch that contains 1 FN and no FP. Or a sketch that contains 1 FP and no FN. If you can draw either of those sketches, A is incorrect. If you cannot draw a sketch without including both 1 FN and 1 FP, A is correct.

In other words, you shouldn't go selecting (A) because you've tried to create a sketch that contains no FN and no FP and failed. Better to try creating a sketch that contains 1 FN or 1 FP but not both.

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Re: PT32 Game 2...."Must at least select..."

Postby Easy-E » Fri Apr 15, 2011 5:29 pm

soj wrote:Sorry, that was confusing, I admit.

The AC is "one FN and one FP."

If A were TCR, you would not be able to draw a sketch that contains no FN and no FP. However, being unable to draw a sketch that contains no FN and no FP doesn't necessarily mean A is TCR.

"A is TCR" is the sufficient statement.
"unable to draw a sketch that contains no FN and no FP" is the necessary statement.

Can you see why? Even if the necessary statement were true (and ignoring the fact that it's always easier to eliminate wrong ACs than to find TCR in a question like this), you might still be able to draw a sketch that contains 1 FN and no FP. Or a sketch that contains 1 FP and no FN. If you can draw either of those sketches, A is incorrect. If you cannot draw a sketch without including both 1 FN and 1 FP, A is correct.


In other words, you shouldn't go selecting (A) because you've tried to create a sketch that contains no FN and no FP and failed. Better to try creating a sketch that contains 1 FN or 1 FP but not both.


I think I follow. Just because you create a sketch that doesn't contain FN and FP doesn't mean that A would be correct, since we don't necessarily know that both of those are the very least needed, it could just be one of the conditions. Or do I not follow?


So my initial plan of attack for this question was right, I just went at the choices that included "and" incorrectly?

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Re: PT32 Game 2...."Must at least select..."

Postby soj » Fri Apr 15, 2011 5:40 pm

Yeah, exactly.

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Re: PT32 Game 2...."Must at least select..."

Postby Easy-E » Fri Apr 15, 2011 7:53 pm

soj wrote:Yeah, exactly.


Thanks for the help, it was immensely useful.

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Easy-E
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Re: PT32 Game 2...."Must at least select..."

Postby Easy-E » Sat Apr 16, 2011 3:55 pm

Follow up to this question, anyone think of some other examples of this "must at least select" type of question showing up in a game?

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soj
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Re: PT32 Game 2...."Must at least select..."

Postby soj » Sat Apr 16, 2011 3:59 pm

I don't remember particular games, but IN/OUT games (e.g. birds in a forest) tend to have this kind of question. Going through the Selection games in the Grouped By book might help.

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Easy-E
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Re: PT32 Game 2...."Must at least select..."

Postby Easy-E » Sat Apr 16, 2011 4:18 pm

soj wrote:I don't remember particular games, but IN/OUT games (e.g. birds in a forest) tend to have this kind of question. Going through the Selection games in the Grouped By book might help.


Yeah, I just finished the In/Out games portion of Steve Schwartz's study guide, and I didn't run into problems with any of the other games. I'll look through the similar games though and see if I can find any questions worded like this.




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