I don't get the Bernoulli Equation right

[AaronBrown]

Your math is perfect, your interpretation slightly off. You are computing the probability of making exactly two of your flush draws.

If you want the probability of making at least two of your flush draws, you have to sum the results of your equation from two to eleven or forty (you'll save time by computing for zero and one, then subtracting that total from 1). There's also a Normal approximation that doesn't require summations.

If you want the expected number of successful draws, just multiply the probability by the number of attempts.