Odds of two people flopping a flush?

[Ace7469]

I just read a thread about calculating the odds of flopping a flush draw as 3*(39*11*10)/(50*49*48)= 10.94%. I am wondering if the odds of flopping a flush is calcualted as follows: 3*(11*10*9)/(50*49*48)= 2.53%? If that is correct, are the odds of 2 people flopping a flush calculated as 3*(9*8*7)/(50*49*48)= 1.29%? Just curious if anyone knows for sure?

[Pokey]

I'll give it a shot, but I'm not 100% sure I'm correct, here, so take this with a grain of salt.

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I am wondering if the odds of flopping a flush is calcualted as follows: 3*(11*10*9)/(50*49*48)= 2.53%?

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I think it should be <font color="red">1</font>*(11*10*9)/(50*49*48) = 0.84%. The "multiplying by three" part referred to the idea that it didn't matter whether the non-flush card was the first, second, or third spot on the flop, so we had to multiply the possibilities by three to account for each. Otherwise, we'd be looking for the odds that the flop came with a non-flush card first, and then two flush cards. Since your question requires all three cards to be flush cards, there's no need to multiply for different orderings; that's already accounted for in the (11*10*9) part.

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are the odds of 2 people flopping a flush calculated as 3*(9*8*7)/(50*49*48)= 1.29%?

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Well, In order for two people to flop a flush, you need to have:

1. Two people with the same flush draw pre-flop, and
2. Three flush cards from that suit on the flop.

The answer depends on your perspective on the question. What starting conditions are true? There are, therefore, a few different ways to answer this question, and they rapidly outpace my ability to answer them, so I'll pose the only one that I can easily solve:

<font color="blue">A. I have suited downcards heads-up. What are the odds that I hit my flush on the flop and the other player does the same thing?</font>

The odds of this are equal to the odds of drawing five suited cards in a row from a deck that's been depleted of two of that suit:

(11*10*9*8*7)/(50*49*48*47*46) = 0.02%.

Adding in other players will obviously increase the chances of you accomplishing your draw, but for the life of me I can't remember how to do it correctly -- sorry.