Probability of straight flush on board

[Playaz]

This happened to me a few days ago at the local dogtrack. The dealer put out a straight flush on the board, and on the very next hand she put out a fullhouse on the board. Then she followed that by almost putting out 4 of a kind but only got 3 7's out

What are the odds of the straight flush on the board? And of it being followed by the fullhouse?

[Lost Wages]

To an observer, i.e. you have no cards, there are C(52,5) = 2,598,960 possible boards. There are 10 possible straight flushes in each suit (A2345 thru JTQKA) for a total of 40.

Probability = 40/2,598,960 = 0.00154% or once every 64,973 hands. So, if you play 30 hands/hr and 40 hr/week, you should see it about once a year.

For the full houses there are 13*12*C(4,3)*C(4,2) = 3744.
Probability = 0.144% or once every 694 hands.

Lost Wages