How long will it take Derrick to save $2,000 for the down payment if he continues to add $50 every month

A4-year project has an annual operating cash flow of $59,000. at the beginning of the project, $5,000 in net working capital was required, which will be recovered at the end of the project. the firm also spent $23,900 on equipment to start the project. this equipment will have a book value of $5,260 at the end of the project, but can be sold for $6,120. the tax rate is 35 percent. what is the year 4 cash flow?