Hi, I am working on some Statistics homework and I am having trouble figuring out my homework. I have 5 questions that I am stuck on. The first one is:

You buy a lottery ticket to a lottery that costs $10 per ticket. There are only 100 tickets available to be sold in this lottery. In this lottery there is one $400 prize, two $105 prizes, and four $30. Find your expected gain or loss. (Round your answer to two decimal places.)