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A Math Riddle
Dec. 6th, 2021 03:59 pmReposting this riddle from Tanya Khovanova's Math Blog, so that I can put the solution behind a link:
Four wizards, A, B, C, and D, were given three cards each. They were told that the cards had numbers from 1 to 12 written without repeats. The wizards only knew their own three numbers and had the following exchange.
A: "I have number 8 on one of my cards."
B: "All my numbers are prime."
C: "All my numbers are composite. Moreover, they all have a common prime factor."
D: "Then I know the cards of each of you."
Given that every wizard told the truth, what cards does A have?
( Solution )
Four wizards, A, B, C, and D, were given three cards each. They were told that the cards had numbers from 1 to 12 written without repeats. The wizards only knew their own three numbers and had the following exchange.
A: "I have number 8 on one of my cards."
B: "All my numbers are prime."
C: "All my numbers are composite. Moreover, they all have a common prime factor."
D: "Then I know the cards of each of you."
Given that every wizard told the truth, what cards does A have?
( Solution )
