A bag contains 4 white marbles and 4 black marbles. If each of 4 girls and 4 boys randomly selects and keeps a marble, what is the probability that all of the girls select the same colored marble?
Choose the correct choice:
A) 1/35 B) 1/9 C) 1/10 D) 1/20 E) 1/30
first, total ways to select for all boys and girls, i.e 8!/(4!*4!) = 8*7*6*5*4*3*2*1/4*3*2*1*4*3*2*1=70   then there are one two way girls can have all same colors, either white or black.   The number of ways in which 4 girls can select 4 white balls = 4C4 = 1   The number of ways in which 4 girls can select 4 black balls = 4C4 = 1   Therefore, total favorable outcomes/total outcomes = 2/70= 1/35   1/35
<result>A</result>
A bag contains 4 white marbles and 4 black marbles. If each of 4 girls and 4 boys randomly selects and keeps a marble, what is the probability that all of the girls select the same colored marble?