Need forumla's used to derive solution.

SI is considering investing in a new product named Z-90. There is a 50% chance that the product will be a success which then generates $110,000 cash inflow each year for the next 5 years. There is a 50% chance that the product will fail which then generates $25,000 cash inflow each year for the next 5 years. The project requires an initial investment of $250,000. Based on the above information, what is the Z