A machine was purchased 7 years ago for $9, 000. Its present market value is $5, 000. and its operating expenses are expected to continue at $1, 000 a year. A second hand machine costing $2, 000 is available, but its operating expenses are expected to be $1, 600 per year. It is anticipated that the machines will be In service for 6 more years with $1, 000 salvage value for the present machine and zero for the second-hand machine. Using the 'outsider viewpoint-, and interest rate of 12%, find the best course of action for a 6 - year study period