SOLUTION: A deck of 10 cards consists of 7 cards that are black on both sides, and 3 cards that are black on one side and white on the other. 2 cards are selected randomly and placed flat o

Algebra ->  Probability-and-statistics -> SOLUTION: A deck of 10 cards consists of 7 cards that are black on both sides, and 3 cards that are black on one side and white on the other. 2 cards are selected randomly and placed flat o      Log On


   



Question 1078120: A deck of 10 cards consists of 7 cards that are black on both sides, and 3 cards that are black on one side
and white on the other. 2 cards are selected randomly and placed flat on the table. Calculate the
probability that 1 black and 1 white side are showing.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
So don't think of the cards as cards but think of the cards as sides of cards in a bag.
So there are 20 sides in the bag, 3 sides are white, 17 sides are black.
P%28B%2CW%29=P%28B%29P%28W%29%2BP%28W%29P%28B%29
P%28B%2CW%29=%2817%2F20%29%283%2F19%29%2B%283%2F20%29%2817%2F19%29
P%28B%2CW%29=51%2F380%2B51%2F380
P%28B%2CW%29=51%2F190