SOLUTION: A box contains N white and M black balls. Balls are randomly selected one at
a time, until a black one is obtained. If we assume that each selected ball is
replaced before the ne
Algebra ->
Probability-and-statistics
-> SOLUTION: A box contains N white and M black balls. Balls are randomly selected one at
a time, until a black one is obtained. If we assume that each selected ball is
replaced before the ne
Log On
Question 1199989: A box contains N white and M black balls. Balls are randomly selected one at
a time, until a black one is obtained. If we assume that each selected ball is
replaced before the next one is drawn, What is the probability that
a) Exactly n draws are needed.
b) At least K draws are needed. Answer by ikleyn(52778) (Show Source):
You can put this solution on YOUR website! .
A box contains N white and M black balls. Balls are randomly selected one at
a time, until a black one is obtained. If we assume that each selected ball is
replaced before the next one is drawn, What is the probability that
a) Exactly n draws are needed.
b) At least K draws are needed.
~~~~~~~~~~~~~~~
In this my post, I will solve part (a), ONLY.
Event in part (a) is the intersection of two indepedent events E and F.
Event E is that first (n-1) draws are white balls.
Event F is that the n-th draw is a black ball.
Therefore, the probability of event in part (a) is
P(event in part (a) ) = . ANSWER
