Find Probability distribution and the expected value

Question

A non-profit organization sells 10,000 raffle tickets at $1 per ticket. There is one grand prize of $3,000, 4 prizes of $500 each and 10 prizes worth $50 each. You buy one of the tickets. Let the random variable X represent your net "winnings". Write out the probability distribution and find the expected value of X.

Answer 1

Net Winnings = Expected value of return - Cost of Ticket

The cost of ticket is $1. The expected value of return can be computed as:

3,000 * (1/10000) + 500 * (4/10000) + 10 * (50/10000) + 0 * (9945/10000) = .325

So, the expected value of net winnings is .325 - 1 = -.675