
Probability and Statistics Basic Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
October 25th, 2017, 09:14 PM  #1 
Newbie Joined: Oct 2017 From: Camboja Posts: 5 Thanks: 0  I need help to calculate a simple problem in probability
Hi folks, i'm not from math field, but i have a question, 1 If in 10 times of event A will occur 2 times event B inside A 2 i know that the chance of event B to occur in sequence is 9, right? x x         1  x x        2   x x       3    x x      4     x x     5      x x    6       x x   7        x x  8         x x 9 3 Then i question, how can i calculate how many times can event B occur NOT in sequence? and how to calculate it? for example  x  x       thanks a lot for any help 
October 25th, 2017, 10:52 PM  #2 
Senior Member Joined: Sep 2015 From: USA Posts: 1,755 Thanks: 899 
There are $\dbinom{10}{2}=45$ ways that 2 x's can occur out of the 10 events. You showed there are 9 ways that the two x's can occur sequentially. Thus there are 459=36 ways the two x's can occur nonsequentially. Last edited by romsek; October 25th, 2017 at 10:55 PM. 
October 25th, 2017, 10:59 PM  #3 
Newbie Joined: Oct 2017 From: Camboja Posts: 5 Thanks: 0 
thanks for answering, i was thinking it was way more thank 100 possibilities, have a nice day


Tags 
calculate, probability, problem, simple 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Simple problem on Conditional Probability  beesee  Probability and Statistics  1  November 1st, 2014 04:50 PM 
Simple probability problem  limes5  Probability and Statistics  9  April 5th, 2014 06:34 AM 
Simple probability problem  please help! :)  drwmn  Probability and Statistics  1  October 10th, 2011 11:03 AM 
Simple probability problem...  Tyster  Algebra  2  September 27th, 2009 05:48 PM 
Probability problem (intuitively simple)  johnny  Algebra  4  August 2nd, 2009 04:33 AM 