There are 3 sisters. Two of them are married, two are blonde and two are secretaries.
The one who is not blonde is not a secretary, and the one who is not a secretary is single. How many, if any, are blonde, married secretaries?
From the book, "The magic garden of George B. and other logic puzzles" by Richard Smullyan.
Difficulty rating:
Easy. 2.5/10
Solution:
It is given that the one who is not blonde, is not a secretary. Since there are 2 secretaries and 2 blondes, it means that both the blonde girls are secretaries.
It is also given that the sister who is not a secretary, is single. Since there are two married sisters, it means that both the secretaries are married.
Therefore, there are 2 blonde, married secretaries.