DS : Probability question

[syedhaneef]

[Deleted because this question is from a banned source - see below.]

[tim]

OG is a banned source; it is illegal to post OG questions anywhere on the web.
If you are in one of our classes, please ask OG questions during office hours or before/after class.

Note that I have also deleted all responses to this question because they all substantially referenced the original problem..