Posted by Chris on Tuesday, January 29, 2013 at 10:54pm.
Can somebody help me solve this problem ? I am not so good with probability. 
A bag contains 2 green marbles and 3 white marbles. One marble is drawn at random and not replaced.
Then a second marble is drawn. What is the probability that the first marble is white and the second one
is green?

Math  Reiny, Tuesday, January 29, 2013 at 10:58pm
Prob(white, then green)
= (3/5)(2/4) = 3/10
Can you tell where my numbers came from ? 
Math  Chris, Tuesday, January 29, 2013 at 11:01pm
3/5 came from the probability of drawing White marbles. I am not sure about the (2/4)

Math  Reiny, Tuesday, January 29, 2013 at 11:22pm
since you kept the first marble drawn, there are now only 4 left, but the 2 greens are still in there
so 2/4 for the greens 
Math  Chris, Tuesday, January 29, 2013 at 11:23pm
Okay , that makes sense .