Methods2023 Exam 2 Section A · Q8CAS active1 mark

Probability of at least one green ball with replacement

A box contains $n$ green balls and $m$ red balls. A ball is selected at random, and its colour is noted. The ball is then replaced in the box.

In 8 such selections, where $n \neq m$ , what is the probability that a green ball is selected at least once?

1 mark

8\left(\frac{n}{n+m}\right)\left(\frac{m}{n+m}\right)^{7}

1-\left(\frac{n}{n+m}\right)^{8}

1-\left(\frac{m}{n+m}\right)^{8}

1-\left(\frac{n}{n+m}\right)\left(\frac{m}{n+m}\right)^{7}

1-8\left(\frac{n}{n+m}\right)\left(\frac{m}{n+m}\right)^{7}

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