Green Lab plans to purchase a new centrifuge machine for its Saskatchewan facility. The machine costs $ $158$ comma $000$ and is expected to have a useful life of $9$years$,$ with a terminal disposal value of $ $3$ comma $000.$ Savings in cash operating costs are expected to be $ $37$ comma $500$ per year.$$ However, additional working capital is needed to keep the machine running efficiently. The working capital must continually be$$ replaced, so an investment of $ $12$ comma $000$ needs to be maintained at all$$ times, but this investment is fully recoverable$($will be$$ "cashed in$")$ at the end of the useful life. Green Lab$\text{'}$s required rate of return is $12\%.$ Ignore income taxes in your analysis. Assume all cash flows occur at$$ year$-$end except for initial investment amounts. Green Lab uses$$ straight$-$line depreciation for its machines. Required

Calculate net present value.

Calculate internal rate of return.

Calculate accrual accounting rate of return based on net initial investment.

Calculate accrual accounting rate of return based on average investment.

You have the authority to make the purchase decision. Why might you be reluctant to base your decision on the DCF$$ methods?