perplexus.info :: Logic : Formal Reasoning

Formal Reasoning (Posted on 2004-12-15)

I present to you a deck of 4 cards. Each card has on one side a letter of the alphabet, and on the other side a single digit from 0-9.

I propose a hypothesis that may apply to this deck:
If the letter is 'E', then the number on the other side is '4'.

I then drop the 4 cards on the table, and you see: 'B', '7', 'E', '4' (on the respective cards).

Which of the 4 cards must you turn over to verify or disprove my hypothesis?

See The Solution Submitted by SilverKnight

Rating: 3.0000 (22 votes)

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

Subject	Author	Date
answer	K Sengupta	2008-02-21 14:28:34
my thoughts	brad	2005-03-29 21:07:48
More thoughts on my previous answer	NetGoofy	2005-03-23 19:13:20
How about this.	NetGoofy	2005-03-23 19:05:04
Maybe?	Kardo	2005-03-23 06:11:47
Turn the E and 7	jim jones	2005-03-15 10:48:53
Turn the E and 7	jim jones	2005-03-15 10:48:53
No Subject	Ujjawal	2005-03-11 13:16:04
solution	Jeff	2005-03-09 04:04:09
re(5): Solution	Dustin	2005-03-07 01:20:18
re(4): Solution	Sean	2005-03-07 00:37:42
re(3): Solution	Dustin	2005-03-06 23:14:23
re(2): Solution	Sean	2005-03-06 23:08:48
re: Solution	artemis	2005-03-06 15:33:10
Solution	Sean	2005-03-06 08:47:21
Solution	artemis	2005-03-05 17:00:38
The REAL Solution	NetGoofy	2005-03-01 17:45:33
solution	aq	2005-02-28 20:53:46
Possible Solution	Robyn	2005-02-23 17:49:35
solution	james	2005-02-22 01:48:53
solution.	Pete	2005-02-10 23:30:04
CORRECTION!!!	dev e.	2005-02-07 02:29:12
weird...	dev e.	2005-02-07 02:01:08
the solution	durrell	2005-02-05 16:42:17
solution	juan m. perez	2005-02-04 22:20:48
the answer	derek	2005-01-19 23:46:10
re: answer	jeff	2005-01-19 07:41:27
answer	jeff	2005-01-19 07:40:08
answer	Cassandra	2005-01-02 01:21:05
answer	jenni	2004-12-27 23:16:56
ANSWER	SIMONE FOLK	2004-12-24 19:44:14
answer???	sarah	2004-12-22 05:33:11
I think this is it	mick	2004-12-19 03:58:29
re: The Answer	gregory	2004-12-19 01:13:19
The Answer	Chris, Phd	2004-12-19 00:32:11
Correcrt Solution	debajit	2004-12-18 09:39:12
solution	daniel	2004-12-17 23:27:10
Tis the Reason	RandyOrton	2004-12-17 14:38:59
Solution	Richard Carr	2004-12-17 13:46:38
possible solution	tawnya	2004-12-17 06:07:06
re: I don't understand	Penny	2004-12-17 02:13:45
I don't understand	Dainma Felpry	2004-12-17 00:11:13
Solution by counterexample	e.g.	2004-12-16 10:52:25
re: solution-and i did not steal it, promise	Nosher	2004-12-16 02:34:07
solution-and i did not steal it, promise	Linda	2004-12-15 20:31:25
Solution	Eric	2004-12-15 17:23:06
Good problem	SteveH	2004-12-15 17:18:28
re: Solution	Federico Kereki	2004-12-15 17:08:10
solution	bob909	2004-12-15 16:46:32
Solution	Joshua	2004-12-15 16:24:32
re: Layman's Logic	Penny	2004-12-15 16:09:03
Layman's Logic	Juggler	2004-12-15 15:50:28
re: 3 Scenarios	Timothy Bard	2004-12-15 15:42:24
re: Solution	Penny	2004-12-15 15:40:00
re: Is there a catch ?	Federico Kereki	2004-12-15 15:23:50
Solution	Penny	2004-12-15 15:14:04
re: 3 Scenarios	nikki	2004-12-15 13:58:47
3 Scenarios	Syzygy	2004-12-15 13:23:56
Is there a catch ?	Syzygy	2004-12-15 13:16:50
Solution	Old Original Oskar!	2004-12-15 12:59:10

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