RCC is a tier 1 Automotive Supplier. They are choosing between two 3-D printing machines, A and B, of comparable specifications to help reduce the time needed in building prototypes for new parts and subassemblies. The company has a MARR (Minimum Acceptable Rate of Return) of 8%. Expected salvage value for each of the two 3-D printing machines at the end of their service lives is $7,500. Answer the following questions using the information in the table below.

	3-D Printine Machine A	3-D Printine Machine B
Down payment	$11,000	$12,000
Running cost per Year	$1,000	$900
	$150 for the first year, increasing by $110/year thereafter	$160 for the first year, increasing by $100/year thereafter
Service cost per year	$3,000	$2,800
Service Life	10 years	12 years

a) State the necessary assumption for comparing mutually exclusive alternatives of different lives?

b) Based on Annual Worth comparison, which alternative should be selected?
c) Based on Present Worth comparison, which alternative should be selected?
d) Do both methods (Present Worth and Annual Worth) always yield the same decision?
e) For a ten-year study period, what salvage value for Machine B would make it a better choice?