A box contains 4 red chips and 4 blue chips. If two chips are selected at random without replacement, what is the probability that the chips are different colors?
Pick one: A) 1/2 B) 4/7 C) 7/12 D) 2/3 E) 7/10
Total selection ways: 8C2=8!/4!4!=28   Selecting one blue chip out of two: 4C1=4!/1!3!=4   Selecting one red chip out of four: 4C1=4!/1!3!=4   Thus, (4C1*4C1)/8C2=(4*4)/28=16/28=4/7=4/7
<result>B</result>
A box contains 4 red chips and 4 blue chips. If two chips are selected at random without replacement, what is the probability that the chips are different colors?