A very similar (if not identical) question was asked here: https://brainly.com/question/12939730 (and up to 4 separate times)
For a game involving winnings, the expected value of one's winnings is simply the sum of the products of each possible amount X one can win multiplied by the probability of winning that amount X.
As I showed in the linked question, you need to have a probability mass function on-hand in order to find the EV. In that question, I go on to derive the probabilities for each possible outcome. Whether your question is the same or you're considering a game with different rules, hopefully you find that solution helpful.
