Envelopes (Posted on 2003-04-10)

	Submitted by Ravi Raja
Rating: 2.9091 (11 votes)
Solution:	(Hide)
Let us assume that the Formula is in Envelope 1. In that case both the statements on the First Envelope as well as on the Second Envelope are False, violating the given conditions of the problem. So the Formula is not in Envelope 1. (Since the problem states that : "The statements on one of the envelopes are BOTH TRUE, the statements on the other envelope are BOTH FALSE and the remaining envelope has ONE TRUE and ONE FALSE statement"). Next assume that the Formula is in Envelope 2. In this case we see that one statement written on each of the Second and Third envelopes is True and the other is False. Again violating the given conditions of the problem. So the Formula is not in Envelope 2. Finally let us assume that the Formula is in Envelope 3. Now we see that the statement (a) on the First Envelope is True whereas statement (b) is False. Both the statements on the Second Envelope are True and both the statements written on the Third Envelope are False, thus satisfying all the conditions of the problem. Hence we conclude that the Formula is in Envelope 3.

	Subject	Author	Date
	Explanation to Puzzle Answer	K Sengupta	2022-06-13 22:08:43
	Puzzle Answer	K Sengupta	2022-06-13 11:31:35
	Solution without using case-by-case analysis	Brian Smith	2017-01-02 14:03:56
	A different method	Gamer	2008-04-06 15:20:38
	Search, Find	FrankM	2008-04-06 09:37:32
	Answer	Praneeth	2007-08-29 06:45:12
	Solution	Bob	2005-03-09 22:24:24
	I got it	John	2004-09-19 03:27:30
	Solution	Lewis	2003-07-25 22:26:41
	re(4): this is easy	Ravi Raja	2003-04-30 19:34:10
	re(3): this is easy	Michael	2003-04-23 23:10:16
	Explanation...	Tim Axoy	2003-04-17 11:33:26
	re(2): this is easy	Ravi Raja	2003-04-15 21:57:40
	re: this is easy	Ravi Raja	2003-04-15 21:45:24
	re: this is easy	Steven	2003-04-15 06:53:38
	this is easy	tony	2003-04-14 10:38:09
	re: 1 and 2,true and true.	Ravi Raja	2003-04-13 04:54:38
	re: Hunting for the formula	Ravi Raja	2003-04-13 04:48:23
	re: HAHA! i think i got it	Ravi Raja	2003-04-13 04:44:30
	1 and 2,true and true.	Tim Axoy	2003-04-13 04:21:59
	re(2): Solution	Ravi Raja	2003-04-13 04:19:49
	Hunting for the formula	Tim Axoy	2003-04-13 04:18:55
	re: My thought	Ravi Raja	2003-04-13 04:15:20
	re(2): Is it that straightforward?	Ravi Raja	2003-04-13 04:07:12
	re: Is it that straightforward?	Ravi Raja	2003-04-13 04:05:20
	HAHA! i think i got it	Steven	2003-04-12 20:13:52
	re: solution	Steven	2003-04-12 20:03:27
	re: Solution	john	2003-04-12 15:42:41
	re: easy way to solve this type of problem	john	2003-04-12 15:38:49
	My thought	Jessica Price	2003-04-11 21:04:38
	re: Is it that straightforward?	Andrew F	2003-04-11 17:30:45
	Is it that straightforward?	Andrew F	2003-04-11 17:20:55
	re: solution	Ravi Raja	2003-04-10 22:24:08
	easy way to solve this type of problem	Jon	2003-04-10 10:03:22
	re: solution	austin	2003-04-10 08:19:19
	solution	austin	2003-04-10 08:13:20
	entertaining	The Mighty Puck	2003-04-10 06:45:27
	answer	DuCk	2003-04-10 03:08:08
	Solution	DJ	2003-04-10 02:51:15