SOLUTION: a bag contain 6 red balls and 5 black balls.two balls are picked one after the other.find the probability that:(i)both are black (ii)the first is black (iii)both are the same colou

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Question 1159446: a bag contain 6 red balls and 5 black balls.two balls are picked one after the other.find the probability that:(i)both are black (ii)the first is black (iii)both are the same colour
Found 2 solutions by LChester89, ikleyn:
Answer by LChester89(3)   (Show Source):
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(i) The probability of picking the first black ball is 5/11. There are originally 5 black balls out of the total 11. The probability of the second ball being black is 4/10 or 2/5 (when you simplify). The total number of black balls is 4 now because you have already taken one black ball out, and the overall number of balls is also one less after taking the first black ball out. To find the probability of both of these events happening in succession, you multiply 5/11 by 4/11, which gives you a probability of 20/121.
(ii) The probability of picking the first black ball is 5/11. There are originally 5 black balls out of the total 11.
(iii) The probability of both balls being black would be 20/121 (please refer to my answer to i). The probability of both balls being red would be 6/11 * 5/10, which would give you 30/110, or 3/11 (when simplified). (Again, the reasoning for both balls being red would be the same as my answer to i.)

Answer by ikleyn(52781)   (Show Source):
You can put this solution on YOUR website!
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            Every day we solve 3 - 5 such problems . . .

(i) P = = = . (ii) P = . (iii) P = P(both are red) + P(both are black) = + = + = .