perplexus.info :: Logic : Three guys, three numbers

Three guys, three numbers (Posted on 2009-05-01)

Three logical people, A, B, and C, are wearing hats with positive integers painted on them. Each person sees the other two numbers, but not her own, and each person knows that the numbers are positive integers and that one of them is the sum of the other two.

They take turns (A, then B, then C, then A, etc.) in a contest to see who can be the first to determine her number.

During round one, A, B, and C pass. In round two, A and B again pass, at which point C states that she now knows all three numbers and that their sum is 144.

How did C figure this out?

Submitted by pcbouhid

Rating: 4.0000 (2 votes)

Solution: (Hide)

The numbers are 18, 54 and 72. The problem can be found here and the solution here.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
re(4): Possible solution (spoiler) THATS WHY	Ady TZIDON	2009-05-16 05:42:00
What'd she know, and when did she know it??	ed bottemiller	2009-05-05 12:50:49
re(6): Possible solution (spoiler)	Praneeth	2009-05-04 11:11:15
re: guys or dolls ??	pcbouhid	2009-05-04 10:52:01
re(5): Possible solution (spoiler)	pcbouhid	2009-05-04 10:46:19
guys or dolls ??	Ady TZIDON	2009-05-04 08:02:02
re(4): Possible solution (spoiler)	Dej Mar	2009-05-04 02:37:38
re(3): Possible solution (spoiler)	pcbouhid	2009-05-03 23:58:19
re(2): Possible solution (spoiler)	Dej Mar	2009-05-03 21:03:33
re: Possible solution	pcbouhid	2009-05-03 20:23:57
Possible solution	Harry	2009-05-03 15:18:34
Eliminating two possibilities...	Dej Mar	2009-05-01 23:49:20

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