IE deparment is thinking of replacing the current station ZM-640 in the lab due to performance problems.ZM-640 was purchased 5 years ago and originally cost 30000TL.It has a present realizable MV of 21000TL.A new workstation will require an investment of 38000TL and is expected to have year-end market values(MV) and annual expenses(AE) as follows;(TL means Turkish Lira.You can say dollar instead of it.)

ZM-640	End of Year k	MV,End of Year k(TL)	Annual Expenses,Ek (TL)
	1	18000	9000
	2	15000	7000
	3	12000	6000
	4	6000	5000

New workstation	End of year k	MV,End of Year k	Annual Expenses,Ek(TL)
	1	31000	4000
	2	20000	3000
	3	16000	2000
	4	6000	2000

CHALLENGER

End of Year k	TCk	EUACk
1	?	?
2	?	?
3	?	?
4	?	?

DEFENDER

End of Year k	TCk	EUACk
1	?	?
2	?	?
3	?	?
4	?	?

a)Fill the tables below using a before-tax MARR value of 8% per year.(THE ABOVE DEFENDER AND CHALLENGER TABLES)

b)For how many years should the new workstation be retained in service if purchased?

?

c)Due to budget constraint, keeping ZM-640 is also an option.What is the economic life of the current asset?

?

d)At the end of which year should the defender be replaced?

?