
Probability and Statistics Basic Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
April 4th, 2014, 03:18 AM  #1 
Member Joined: Jun 2012 Posts: 91 Thanks: 0  Cancelling factors.
Hi, In the textbook Introduction to probability, by John E. Freund, there is one section that is not explained very well by the author. He shows two formulas where some factors is canceled, and the only note he gives is "Cancelling as many factors as possible before performing any multiplications, we would thus have obtained....". The attached image shows my recreation of the formulas as they are printed in the textbook. 1. Could someone please explain the logic behind the cancelations in the attached formula? 2. In the second formula, why is number 12 not cancelled? Is there a typo? EDIT ( ItÂ´s obviously a typo in the textbook, thanks MarkFL for pointing that out) Thanks for any help! Last edited by zengjinlian; April 4th, 2014 at 03:36 AM. Reason: picture typo 
April 4th, 2014, 03:29 AM  #2 
Senior Member Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,155 Thanks: 463 Math Focus: Calculus/ODEs 
Yes, the 12 should be cancelled in the computation.

April 4th, 2014, 03:35 PM  #3 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,082 Thanks: 2360 Math Focus: Mainly analysis and algebra  

Tags 
cancelling, factors 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
property of numbers of factors of factors of a number  mathbalarka  Number Theory  15  June 15th, 2012 08:36 PM 
factors for (n!+1) and (n!1)  loaiello  Number Theory  4  February 26th, 2011 09:24 AM 
four different factors  naserellid  Algebra  1  August 14th, 2010 08:22 AM 
Factors  Tartarus  Algebra  7  December 11th, 2009 10:01 PM 
500 factors  coax  Number Theory  6  July 23rd, 2009 09:13 AM 