The Last Baby (Posted on 2003-10-08)

	Submitted by Ravi Raja
Rating: 2.7778 (9 votes)
Solution:	(Hide)
We apply Baye's Theorem here: Let events A1,...,Ak form a partition of the space S such that P(Aj)>0 for j=1,...,k, and let B be any event such that P(B)>0. Then for i=1,...,k, P(Ai|B) = P(Ai)*P(B|Ai) / Sum for j=1 to k of P(Aj)*P(B|Aj). Now let, B=boy selected A1=boy added A2=girl added g=number of girls before baby is added. P(A2|B) = (1/2)*(2/(3+g)) / [(1/2)*(2/(3+g)) + (1/2)*(3/(3+g))] = 0.4

	Subject	Author	Date
	Puzzle Thoughts	K Sengupta	2023-03-28 09:03:22
	re: It really does seem too easy.	Ben	2003-11-28 01:14:00
	It really does seem too easy.	Sara	2003-11-10 19:17:32
	my take	Lee	2003-11-05 00:57:52
	Bayes Theorem	Robert Bell	2003-11-04 13:17:44
	Could be easy.	Bill	2003-10-22 13:19:04
	this is too easy, so easy that it scares me and i probably will mess up	iggyb387	2003-10-15 20:43:25
	re: assumption	Charlie	2003-10-11 23:01:58
	assumption	A	2003-10-11 22:30:37
	No Subject	e	2003-10-09 19:00:47
	re(4): I have not read Charlie's post yet	FatBoy	2003-10-09 12:36:20
	re(3): I have not read Charlie's post yet	SilverKnight	2003-10-09 11:21:29
	re(3): I have not read Charlie's post yet	fwaff	2003-10-09 08:52:48
	re(2): I have not read Charlie's post yet	FatBoy	2003-10-09 07:33:47
	re(3): solution - different manner of looking at this	SilverKnight	2003-10-09 02:23:10
	re(2): solution - different manner of looking at this	Charlie	2003-10-08 22:16:23
	re: solution - different manner of looking at this	SilverKnight	2003-10-08 16:26:52
	re: I have not read Charlie's post yet	Charlie	2003-10-08 15:46:02
	re: does the lightbulb mean they're right?	SilverKnight	2003-10-08 13:52:11
	re: does the lightbulb mean they're right?	FatBoy	2003-10-08 13:41:47
	does the lightbulb mean they're right?	matt white	2003-10-08 13:35:35
	Who else hasn't read Charlie's post yet?	SilverKnight	2003-10-08 13:18:36
	I have not read Charlie's post yet	FatBoy	2003-10-08 13:04:41
	solution	Charlie	2003-10-08 10:25:35