please help with this question. please show all calculations and work. thank you.

Consider a twelve-year project that costs $48,000 today and will produce after-tax cash flows of $6,000 each year for the first four years, $7,000 each year for the next four years, and $8,000 cach yoar for the last four years. If the cost of eapital is 12 percent, what is the project's NPV