A marble shop contains 6 blue marbles, 7 red marbles, and 7 green marbles. If 4 marbles are purchased at random from the shop, what is the probability that the 4 marbles will be blue?	Choose the most appropriate option.
A) 5/19  B) 9/20  C) 1/57  D) 15/57  E) 15/684
It doesn't matter which type of card you choose, so:   Probability of choosing 1st card: 6/20   Probability of choosing 2nd card of the same type: 5/19   Probability of choosing 3rd card of the same type: 4/18   Multiply and you get 1/57   Answer 1/57.
<result>C</result>
A marble shop contains 6 blue marbles, 7 red marbles, and 7 green marbles. If 4 marbles are purchased at random from the shop, what is the probability that the 4 marbles will be blue?