- #1

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 * q

^{n-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...