Need some help with puzzles

Question

I will sit for an exam whose questions are heavily inspired from GMAT. In the analytical section, there are puzzle questions which I can best describe as zebra puzzles. I will give one such question below. I would like to know how to efficiently solve questions like these without going through every possibility, and also some resources for questions like these.

There are 6 books to place on an empty bookshelf with 3 shelves. 3 of the books, X, Y and Z are fiction. The other 3, P, Q and R are non-fiction. The shelves are marked 1, 2 and 3 from top to bottom. Any of the shelves can remain empty. The placement of books must conform to the following conditions-
•P and R cannot be on the same shelf
•X must be immediately above R
•No single shelf can hold all 3 fiction books
•Q cannot be on shelf 2

1) If Y and Z are on shelf 2, which of the following must be true? 
(a) Q is on shelf 1 (b) X and Q are on the same shelf (c) P is on shelf 3 (d) Y and P are on the same shelf (e) R is on shelf 2

2)If shelf 1 is empty, which of the following must be false
(a) Z and X are on the same shelf (b) There are exactly 3 books on shelf 2 (c) Y and Z are on the same shelf (d) There are exactly 2 books on shelf 3 (e) Y and Q are on the same shelf

Sorry for the long post

P.S I do not know if or where zebra puzzles are given in the GMAT examination so I've tagged this as IR.

edit - I'm trying to leave spaces between the options but I am unable to do so.

Sajjad1994 · Answer

This questions seems to be related more to the LSAT than the GMAT so moving this to the right forum. To answer your query nightblade354 has the full right and authority.

nightblade354 · Answer

Sajjad1994 , this is a logic game, which is a major part of the LSAT, so you were right to put it here.

See attached, as it is far easier to illustrate these types of problems.

rocky620 · Answer

I approach these questions by Uncovering the non-conditional elements:
P&Q can be on the same shelf
Q&R can be on the same shelf
X&Y can be on the same shelf
Y&Z can be on the same shelf
Z&X can be on the same shelf

Q1: Must Be true?
Given - Y & Z are on shelf 2

Shelf - 1   = X (Since X has to be above R and all three fictions cannot be on same shelf) 
  Shelf - 2   = Y, Z , R (Same reason as above)
  Shelf - 3   =

Now we are left with  Q & P  and both can be placed anywhere on either Shelf 1 or Shelf 3.

(a) Q is on shelf 1...It can be on Shelf 3
(b) X and Q are on the same shelf.....Q can be on Shelf 3
(c) P is on shelf 3....Can be on shelf 1
(d) Y and P are on the same shelf.....Definitely not. As P cannot be with R
  (e) R is on shelf 2......  Yes we have already established this.

Q2 : Must Be false?
Given - Shelf 1 is empty

Shelf - 1   = 
  Shelf - 2   = X, P (X above R, P not with R)
  Shelf - 3   = R, Q (R below X, Q not on Shelf-2)

Now we are left with  Y & Z  one of them can be placed on Shelf 2. But both of them can be placed together on Shelf 3.

(a) Z and X are on the same shelf....Can be true if Y is on Shelf 3
(b) There are exactly 3 books on shelf 2...It can be true, if either of Y & Z is placed on Shelf 2
(c) Y and Z are on the same shelf....Not always false.
  (d) There are exactly 2 books on shelf 3.....  This will always be false as Y & Z cannot be on shelf 2 together. SO one has to be on the Shelf3
(e) Y and Q are on the same shelf....Y can be on Shelf 2

StudyingTree · Answer

Thanks for the answers guys.

GmatTest2026 · Answer

Hi Experts,

I need to practice a bunch of questions on LSAT logical puzzles. Where do I find such questions?  Sajjad1994 , nightblade354 
Can anyone please help me?

Thanks in Advance!

Need some help with puzzles

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia