Answer:
(a)

(b)
-1
(c)
30
Explanation:
(a)
Your random variable will have two possible values, 30 and 0, one of them with a probability of 0.45 and the other one with a probability of 0.55. Therefore it looks like this.

(b)
The expected value of this PMF would be
therefore on average you will have a dollar less.
(c)
For this one, if you play 20 times and your initial amount is 50$ then you have to compute the following expectation.
![E[50+20*X] = 50+20*E[X] = 50-20 = 30](https://img.qammunity.org/2021/formulas/mathematics/college/9a2jpevldg7oadb031r6nhrnt5otf4z38b.png)