What are the chances of pulling two balls of the same colour from a bag containing [math]m[/math] white balls and [math]n[/math] black balls?[br][br]If you'd like the probability to be exactly [math]\frac{1}{2}[/math], which amounts of white and black could you use?[br][br](source - Jonny Griffiths - Making Stats Vital - [url=http://www.s253053503.websitehome.co.uk/msv/msv-23.html]http://www.s253053503.websitehome.co.uk/msv/msv-23.html[/url])