An engineer uses an economic analysis to determine which of three different machines to purchase. All the machines that are being evaluated are capable of performing the same task. Assume the minimum attractive rate of return of 6%. Use the in rental IRR analysis. Which is the best economic investment? Initial cost $13.000 $23,000 $21.00 Estimated life 9 years 9 years 9 years Salvage value $2.000 $2, 600 $2.800 Annual maintenance cost $450 $575 $475 Annual income $3.450 $3.675$1.800