adding probability: prob. 2 of 3 are white, given 6 red, 5 w

[totoro]

there are 6 red and 5 white marbles. Three are selected. Whats the probability that you get at least 2 white marbles?

the answer is supposed to be 14/33 but i keep getting 26/165

 

[royhaas]

Re: adding probability

There are three ways to get exactly two white marbles and 1 red marble. Use that to calculate the probability of exactly two while marbles, then add the probability of three whites in a row.