Online Course Discussion Forum

math challenge II-A combinatorics 9.22

 
 
Picture of John Lensmire
Re: math challenge II-A combinatorics 9.22
by John Lensmire - Tuesday, October 5, 2021, 11:34 AM
 

The probability should be 5 / 9 here. Consider the drawing below of the 3 by 3 grid which plots the arrival times of Jack and George:


5 of the 9 regions are shaded, hence the probability 5/9.