An urn contains 6 red, 7 white and 5 blue balls. Consider the experiment of drawing 4 balls uniformly at random, with no order assigned to the balls drawn.

Let A = "At least 3 white balls are drawn" and B = "Exactly one drawn ball is red"

i) Calculate P(A), P(B), and P(A n B) - read as probability of the intersection of A and B.

ii) Does knowing A has occurred increase the chances that B also has occured?

iii) Does knowing B has occurred increase the chances that A also has occured?

For part i) I am lost on how to get P(A). I thought about the outcomes of white and got 7/18 + 6/17 + 5/16 but this yielded a number larger than 1, and I assume this number should be relatively small.

P(B) = .083333 I took 6/18 and divided that value by 4.

ii) I believe A does increase the the chances of B because there are now less white balls to choose from.

iii) I believe B does NOT increase the chances