Continuous random variables

Hi, I have this math assignment on continuous random variables and would greatly appreciate some help. This is the question that I am having trouble with:

Sara loves shoes and buys many pairs, but gets tired of them quickly. She throughs them away by the pair only into a dumpster, which is emptied every 3 months. Let X be the number of shoes in the dumpster at any given time and let Y be a continuous random variable which is known to be a good approximation of X.

(a.) whats the numerical value of Pr[X=9] ?

(b.) Find an expression in terms of Y for each of the following:

(i) Pr[X=40] (ii) Pr[X<40] (iii) Pr[X>36]

(c.) If Pr[Y>21] = 1-Pr[X<k], what is the value of k?

Thanks!!