probability of opponent flopping a flush?

[balkii]

I know that if you hold 2 suited cards, the chances of flopping a flush are somewhere around 100:1 (thats right, isnt it?). MY question is:

Heads up, the flop comes three spades, and I dont have any. Is it 100:1 against my opponent having a flush?

[Copernicus]

The precise number is .85% chance of flopping a flush or straight flush (if they started out connected), or 118/1. On the other hand if the flop is 3 of a suit, it is much easier for your opponent to have the flush (whats harder, to add 3 flush cards to two already there, or add 2 to 3 already there?)

The probability he started with two of the suit when you have none is 10/47*9/46 or 4.1%, the odds against it are only 23/1.

[balkii]

ok I was thinking it didnt sound right. Thanks a lot