posted by Bart on .
I do not understand how to figure out probability.
Lee has an urn with 8 white marbles and 10 black marbles. A marble is drawn at random and not replaced. Then a second marble is drawn randomly. What is the probability that the first is white and the second is black?
prob(1st is white) = 8/18
there are now 17 left of which 10 are black , so
prob(2nd black) = 10/17
so prob (of your event) = (8/18)(10/17) = 40/153