Question 8171
without replacement, means you pick one and leave it out and then pick another, so at first we have P(White) = 3/8


Once we have done this, we have 2 whites left in a total of 7, so P(second white) = 2/7


Probability of white AND then white is 3/8 x 2/7 which is 3/28.


If you can never remember to multiply or add, just remember, adding 2 fractions together will give a larger (more probable) number. Multiplying 2 fractions gives a smaller number.


In terms of Probability...you pick a white. You pick 2 whites...the 2 whites is less likely to happen, so smaller probability is expected --> multiply.


Hope this helps.


jon.