PT21.S1.G4 (sequencing w/ a twist #3) - "G is not advertised unless J or else O is also advertised"

minglejingle

Hey guys,

I've been having a lot of trouble understanding the explanation behind this game, which is also explained in the curriculum under sequencing games with a twist as the third example.

There can only be one repeating product on the board. For the rule "G is not advertised during a given week unless either J or else O is also advertised that week", JY says that we know that G cannot repeat b/c it'd carry another component with it. However, I don't understand why this is necessarily known, when G could repeat and bring J one time and bring O the second time. Am I missing something?

Thanks y'all!

https://7sage.com/lsat_explanations/lsat-21-section-1-game-4/
https://7sage.com/lesson/sequencing-game-wa-twist-3-game-board-setup/

akistotle

Hey @minglejingle,

I'm reposting a reply I made 3 months ago in the comments, so let me know if you have any other question!

Sorry, @"J.Y. Ping" jumped the gun in this explanation. But it's true G can't repeat.

In the videos, he says G can't repeat because G carries something with it.
cf. At 5:42 of Sequencing Game w/a Twist 3 - Game Board Setup and 7:25 of LSAT 21 - Section 1 - Game 4.

But we can't say "G can't repeat" right after reading the 3rd rule. In combination of the 5th rule (O is in 3), we know that G can't repeat. G can't repeat because O is in 3.

(Because without the 5th rule, this scenario where G repeats itself is possible: Week 1: K H; Week 2: G J; Week 3: L M; Week 4: G O)

Let's review the set up: There are 7 items. There are 8 slots. Only 1 item gets to repeat (“Exactly one of the products will be a member of two of these four pairs”).

G has to always carry something (J or O).

From the first rule, we can figure it out that J must be in week 2 because:

Why J can’t be in week 1:
It has to have H in the week before.

Why J can’t be in week 3:
G has to be with wither J or O. So if J is with O, G can’t be with them.

Why J can’t be in week 4:
If J is in week 4, week 3 must have H and O. G has to be in week 4 because it has to be with J or O. But if J is in week 4, G has to be the repeated one. So G has to be in week 1 or week 2. But this is not possible because G has to carry J or O with it. In this scenario, we already have J in week 4 and O in week 3. But only one item gets to repeat. So G can’t repeat.

So now we know J must be in week 2. The item that is repeated must be in week 4.

To reconfirm, let’s try to make G-showing-up-twice scenario happen. The item that gets repeated is in week 4 but not in week 3 (2nd rule).

So let's place G in week 4.

week 1: H
week 2: J
week 3: O
week 4: G

Let's say G first appeared in week 1:

week 1: H and G
week 2: J
week 3: O
week 4: G

But G has to carry J/O. So this is not possible.

Let's say G is in week 2:

week 1: H
week 2: G and J
week 3: O
week 4: G and J/O

This is not possible because only one item gets to repeat. J and O already appeared in week 2 and 3 respectively.

Sorry for a very long post! I hope this clarifies a bit.