Consider a piece of equipment for which the expenditure at the beginning of period 1 is $80,000. Given that this is cost, we consider it as negative in a net revenue framework. The net revenue at the end of year 1 is $10,000. The net revenue at the end of year 2 is $20,000. The net revenue at the end of year 3 is $30,000. The net revenue at the end of year 4 is $40,000. This includes revenue from operations and sale of the used equipment. The interest rate is 4%. What is the net present value of this net revenue stream