Playing With Marbles (Posted on 2003-10-13)

	Submitted by Ravi Raja
Rating: 3.1000 (10 votes)
Solution:	(Hide)
The probability of event A happening given that event B already happened is the probability of A and B happening divided by the probability that B happened. This can be pressed as P(A|B)=P(A and B)/P(B). In this case A is drawing a black marble and B is having already drawn a black marble. P(A and B) = (1/2) * [(3/4)^2 + (1/4)^2] = 5/16. Theredore, P(B) = 1/2. P(A|B) = P(A and B)/P(B) = (5/16)/(1/2) = 10/16 = 5/8.

	Subject	Author	Date
	Puzzle Answer	K Sengupta	2022-07-06 23:27:43
	Seven words	ajosin	2005-06-20 03:05:41
	Some Infor	gabbo	2004-09-15 22:11:19
	a possible answer	logischer Verstand	2004-03-21 23:37:55
	Figuring out loud.	PhatFingers	2003-11-09 23:29:35
	Solution	Prab	2003-11-05 09:07:55
	the solution	anand	2003-10-17 14:38:05
	re: no expert	Dan	2003-10-14 19:40:29
	re: no expert	Charlie	2003-10-14 10:42:40
	re: Extension to the problem	Charlie	2003-10-14 10:37:33
	Extension to the problem	Trevor Leitch	2003-10-14 07:16:15
	no expert	nellie	2003-10-14 07:05:04
	Marble not at this......	Dan	2003-10-14 03:02:45
	marble madness	Lee	2003-10-14 01:40:40
	re(4): Have you lost your marbles ?	Dan	2003-10-14 00:47:26
	re(3): Have you lost your marbles ?	DJ	2003-10-13 22:57:12
	re(2): Have you lost your marbles ?	Dan	2003-10-13 21:15:50
	re: Have you lost your marbles ?	Brian Smith	2003-10-13 21:04:14
	Have you lost your marbles ?	Dan	2003-10-13 20:43:39
	re: Could be wrong	DJ	2003-10-13 16:00:08
	Solution	DJ	2003-10-13 15:55:18
	Could be wrong	nikki	2003-10-13 15:47:36
	Solution	Trevor Leitch	2003-10-13 15:25:11