A bag contains 2 white marbles and 2 black marbles. If each of 2 girls and 2 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 from the following choices:  A) 1/35  B) 1/10  C) 1/3  D) 1/4  E) 1/5
first, total ways to select for all boys and girls, i.e 4!/(2!*2!) = 4*3*2*1/2*1*2*1=6   then there are one two way girls can have all same colors, either white or black.   The number of ways in which 2 girls can select 2 white balls = 21/32 = 1   The number of ways in which 2 girls can select 2 black balls = 21/32 = 1   Therefore, total favorable outcomes/total outcomes = 2/6= 1/3   1/3
<result>C</result>
A bag contains 2 white marbles and 2 black marbles. If each of 2 girls and 2 boys randomly selects and keeps a marble, what is the probability that all of the girls select the same colored marble?