Beads in a bag (probability).

Question

There are 2 black, 5 yellow and 3 red beads in a bag. You pick one out, record its color, and replace it. You do this three times. What is the probability that exactly 2 are the same color.

Answer 1

P(black) = 2/10 = 1/5

P(yellow) = 5/10 = 1/2

P(red) = 3/10 on any one draw.

 

P(black,black,black) = (1/5)³ = 1/125

P(2 black, one other) = P(BB- or B-B or -BB) = 3(1/5)²(4/5) Study this to see the reasoning behind it.

Then answer the other two questions, P(2 yellow, one other) and P(2 red, one other).

 

ADD the three probabilities just computed.I hope that this satisfies you--some help, and then encouragement to finish the job yourself. (That's my idea of the best tutoring).