Originally Posted by

**Runty** Unless I misinterpreted by Prof., he said that this question does not involve **binomial random variables**. Mr F says: The random variable is binomial. However, it can be done without using that fact since it boils down to getting Pr(X=0) and this can be done without using the binomial formula.

It is definitely a random variable question, but he said that binomial random variables aren't involved.

As such, your answer to the first part could be wrong. I'm not sure; you're the expert.

EDIT: Just to note, I listed the question word-for-word. That might help with interpretation.

Also, by Pr, do you mean probability mass function? We use $\displaystyle p(a)=P\{X=a\}$ to define that, so there could be a bit of disparity in defining it.