Consider a piece of equipment for which the expenditure at the beginning of period 1 is $40,000 The net cost at the end of year 1 is $8,000. The net cost at the end of year 2 is $10,000. The net cost at the end of year 3 is $16,000. The net cost at the end of year 4 is $7,000. With an interest rate of 5%, what is the net present value of this cost stream at the begining of period 1?