# Math Help - Balls in bags.

1. ## Balls in bags.

consider a bag containing 10 balls of which a few balls are black balls.Probability that the bag contains exactly 3 black balls is 0.6 and the probability of bag containing exactly one black ball is 0.4 now balls are drawn from the bag one at time with out replacement till all black balls have been drawn.The probability that this procedure would end in 6th draw is p

we will use binomial distribution but how

2. ## Re: probabilty 2

Well from the information we can say n=10

Also

P(X=3) = 10C3 p^3(1-p)^7 = 0.6

P(X=1) = 10C1 p^1(1-p)^9 = 0.4

does this help?

Then the question talks about taking the balls without replacement, can binomial be used for this?