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Lolsauce
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Homework Statement
A box contains m white and n black balls. Suppose k balls are drawn. Find the probability of drawing at least one white ball.
Homework Equations
Probability of one success = P({1 successful trial}) = n * p * qn-1
p = probability
where q = 1-p
Fundamental theorem of Bernoulli trials (or k successes):
The Attempt at a Solution
My sample size is m+n. So the probability of white is:
P(W) = m/(m+n)
There are k balls drawn. I did not know if we want the equation for 1 successful trial or k successes, as there is a probability of getting a white ball more than once. I went with the first equation as the keywords "at least one white ball". Using the first equation I get:
p = P(W)
q = 1 -P(W)
P({1 success}) = n (m / (m+n))n(1 - (m / (m+n))n-1
I looked at the solution manual and have no idea how they got the following...