Suppose there are three white marbles and three black marbles in a bag and you want to remove two marbles. What is the probability that you will select a white marble and then a black marble? Express your answer as a percent.

Question

anonymous · Answer

Thank you :)

anonymous · Answer

yeah 50% because there is an equal amount of marbles

anonymous · Answer

ok, just wanted to be sure i was right

anonymous · Answer

thanks!

anonymous · Answer

:)

phi · Answer

The problem says you want to remove two marbles. 
So you do not replace the marble back in the bag.  This changes things.

probability of getting a white marble on the first pick is # of white / total number = 3/6 =1/2
now there are 5 marbles left in the bag: 2 white and 3 black.  Probability of drawing a black marble is 3/5

The probability of getting a white followed by a black is (1/2)*(3/5) = 3/10  or 30%