#7 - Local, Must Be True

[saygracealways]

Hi PowerScore,

I also have the same question as Iceberg.Human. I understand why the correct answer choice is (D) but am wondering why you chose to answer the question by looking only at the placement possibilities of the first N. I solved the question by drawing a quick template with three hypotheticals:

1) N (1) G (3) I (4) N (5)
2) N (1) G (4) I (5) N (6)
3) N (3) G (4) I (5) N (6)

Would this method be considered 'inefficient' and too time-consuming compared to the one posted on this forum under real testing conditions?

Thank you!

-Grace

[Adam Tyson]

Hey there Iceberg.Human and Grace, happy to help! There is nothing about this question that forces us to focus on the first N, and we could have happily selected an answer that said "day 5 or else day 6", for example, because every solution that fits this local restriction must have an N in one of those two slots. They just didn't give us that option!

Grace, I attacked this question exactly the same way you did, with those same three local diagrams. Then I compared the answers to the diagrams, and answer D was the only one that was worked. I don't HAVE to have an N in slot 1, because I have the solution where NGIN is in slots 3 through 6. I don't HAVE to have an N in slot 3, either, because there are solutions with N in slot 1 and the GIN block later. I don't HAVE to have an N in slot 5, because two of those solutions don't have that. And I don't HAVE to have an N in slot 3 or else slot 5 because there is one solution where the Ns are in slots 1 and 6. Only answer D is required - no matter which solution I use, there is always an N in slot 1 or else in slot 3.

In short, it is not the question that makes me focus on the first N, but the answer choices that eventually force me to do so.

[ehlers.christopher]

I am not understanding how this is diagrammed at all, and the official description that you have both here and as part of the HW explanation does not break it down into basic enough terms. How can I better understand this basics of setting up this diagram?

[Ryan Twomey]

Hey ehlers.christopher,


Okay so first the prompt tells us we have 12 entities and six slots available.

First rule: We cannot have a Norwegian in day 2 nor day 4.

2nd rule: Italian-------> Italian Norwegian Block
Contrapositive: No Italian Norwegian block----------> No Italian

This means that if you are going to have an Italian a Norwegian must be the following day.

Deduction: This would give us a no Italian in day 1, a no Italian in day 3, and a no Italian in day 6 because a Norwegian would not be able to follow in any of those days. This may be the part that you didn't quite understand. You have to use the first rule to get the no Italian day 1 and no Italian day 3 deduction.


3rd Rule:

If there is a Greek---------> Greek Italian Block.
Contrapositive: No Greek, Italian, Block-----------> No Greek.
Translation: this means that if you are going to have a Greek you need an Italian the following day

Deduction #1: if there is a Greek-------> Greek Italian Norwegian Block.
Translation: If you have a Greek you need an Italian the following day and a Norwegian the day after that.

Deduction #2: Now you cannot have a Greek in spot six, you cannot have a greek in spot 2, and you cannot have a greek in spot 5.


I really hope this helps!

Best,
Ryan