SOLUTION: A bag contains 100 marbles - 20 red and 80 black. The bag is shaken, a marble is drawn and returned, and the bag is shaken again. This process is repeated 3 more times. Calculate t

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Question 920232: A bag contains 100 marbles - 20 red and 80 black. The bag is shaken, a marble is drawn and returned, and the bag is shaken again. This process is repeated 3 more times. Calculate the probability of drawing
a) exactly 3 black marbles
b) exactly 3 red marbles
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
with replacement..
4 drawings
P(3B) = 4%288%2F10%29%288%2F10%29%288%2F10%29%282%2F10%29 (4 different spots for the non-black to be picked)
p(3R) = 4%282%2F10%29%282%2F10%29%282%2F10%29%288%2F10%29 (4 different spots for the non-red to be picked)