Can you please explain Why P(W2) is 4/9 ? Thanks..
This is because you are searching for the white marbles and there are total 4 white marbles. And the total marbles you've got is 9. So it 4/9.
You don't actually need this method, You just need the probability of the second draw.Because the second draw is without replacement, Total marbles decrease by 1 and now the total is 8, because already a white marble is taken, total no. of white marbles left is 3. So the answer is 3/8. Easy...comment if there is any doubt.