Below is my homework problem. If possible I would like to have the work shown

Below is my homework problem. If possible I would like to have the work shown of how to solve this problem. This way I can understand the
method to solving it. Also I am not allowed to use ecxel to do the calculations.

A project will produce operating cash flows of $60000 a year for four years. During the life of the project inventory will be lowered by
$20000 and accounts receivable will increase by $25000. Accounts payable will decrease by $10000. The project requires the purchase of equipment at an
initial cost of $200000. The equipment will be depreciated straight-line to a zero book value over the life of the project. The equipment will be salvaged at
the end of the project creating a $30000 after-tax cash flow. At the end of the project net working capital will return to its normal level. What is the net
present value of this project given a required return of 12 percent?