Imagine an election between two candidates.
A receives m votes, B receives n votes, and A wins (m>n).

If the ballots are cast one at a time, what is the probability that A will lead all the way throughout the voting process?

(In reply to reference by xdog)

Excellent reference, showing several ways to prove it.

It is however a challenge  to show that  (m-n)/(m+n) is a valid answer for m>=n : without going "copy and paste".

Posted by Ady TZIDON on 2015-10-06 10:54:54