NPV? Can someone pls help? Im lost!!?

A project requires an investment in machinery today of $15 million. That investment can be depreciated for tax purposes straight-line to zero over 5 years. Starting one year from now and ending 4 years from now, the project will generate annual revenues of $17 million and expenses of $12 million, both pretax. An immediate working capital investment of $1 million is required, and working capital will remain at that level until recovered 4 years from now. Also at year 4, the machinery will be sold for $7 million. The firm is taxed at 40%. An appropriate discount rate is 8%. What is NPV? Could u pls explain to me in detail? thank you so much

The answer is $4.97 million. I'll send you a spreadsheet showing the analysis if you email me.

NPV is an investment appraisal technique. Therefore if the project yields a positive NPV the project will most likely be accepted and vice versa.
The NPV of the project if positive 9.09M which indicates that the project will be accepted based on the facts stated in your questions. However there may be other factors to consider when carrying out an NPV.
The project was assessed using a four period. Although you did not state whether or not tax will be paid in the year it arises I assumed that tax will be paid in the year that it arises.
I started the NPV using the revenue figure of $17M provided and deducted the expenses of $12M. I also deducted the tax allowable depreciation of $3M per annum (15/3 - since your question indicated that the machine will depreciated on a straight line basis for 5 years), [The fact that the machine has a life span of 5 years indicates that the project could also have assessed on a 5yr. basis]
I then deducted the tax @ 40% = 0.8M and then added back the tax allowable depreciation since that is not considered a real cash flow.
I then included the the investment of $15M and working capital requirements of $1M and the returns at the end of the 4 year period.
The Net cash flow before discount was Yr1 (16M), Yrs 2-3 5.8M and Yr 4 13.8M
I used the discount factor of 8% [Yr0 - 1; Yr1 - .926; Yr2 - .857; Yr3 - .794; Yr4 - .735
Thus the Present Value of 9.09M