Ravenclaw Tests of Logic


Brilliant, said Hermione.  This isn't magic - it's logic.




Puzzle Five - Silly Snerdly - Solution Page

Snerdly the Poltergeist stole four items from Professor Dybendahl's office (a quill, a book, a key, and a Remembrall) - replacing each with a particularly high-quality herring. He deposited one of the stolen items in each of the four common rooms of the four houses. Professor Dybendahl went to retrieve them, going to each of the four common rooms in turn. Can you match each of the four objects with the Hogwarts common room in which Snerdly left it? And can you find the order in which Professor Dybendahl retrieved them?

  1. At the time Professor Dybendahl retrieved the book, he'd already retrieved the Remembrall, but he hadn't yet gone to the Ravenclaw common room.

  2. When Professor Dybendahl entered the Slytherin common room, he'd already retrieved the key, but had not yet been to the Gryffindor common room.




Solution:

The first place Professor Dybendahl went was not Ravenclaw (clue 1 - he had to go to two places before Ravenclaw), Slytherin (clue 2 - he had to go one place before Slytherin), or Gryffindor (clue 3 - he had to go two places before Gryffindor), so it must have been Hufflepuff.

The second place Professor Dybendahl went was not Ravenclaw (clue 1) or Gryffindor (clue 2), and we've already figured out Hufflepuff was the first place, so the second must be Slytherin.

If the second place is Slytherin, and Professor Dybendahl had already retrieved the key by the time he went to Slytherin (clue 2), then the first object must have been the key.

Professor Dybendahl can't have retrieved the Remembrall third or fourth (clue 1 - he had to go to two places after getting the Remembrall), and we've already figured out the first object was the key. So the Remembrall must have been the second object.

If the Remembrall was the second object, Professor Dybendahl would have to have retrieved the book either third or fourth. But it can't have been fourth, because he still had to make one stop after retrieving the book (clue 1), and so the book must have been third.

If the key is first, the Remembrall is second, and the book is third, the quill must have been fourth.

Since the book is third, and Professor Dybendahl went to Ravenclaw after retrieving the book (clue 1), Ravenclaw must be fourth.

If Hufflepuff is first, Slytherin is second, and Ravenclaw is fourth, Gryffindor must have been third.

So:

Order Common Room Object
First Hufflepuff Key
Second Slytherin Remembrall
Third Gryffindor Book
Fourth Ravenclaw Quill





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