Answer:
Desing A is a better deal as the equivalent annual cost is lower than desing B
Anywa, bot desing cost are above the city collections thus, it cannot afford the sanitary systems unless it raises taxes
Explanation:
Desing A
F0 405,000
operating and maintenance cost 51,000 for 14 years
Present value of the operating and maintenance cost:
[tex]C \times \frac{1-(1+r)^{-time} }{rate} = PV\\[/tex]
C = $ 51,000.00
time = 14 years
rate = 0.07
[tex]51000 \times \frac{1-(1+0.07)^{-14} }{0.07} = PV\\[/tex]
PV $446,018.8673
net worth: $ 851,081.87
equivalent annual cost:
[tex]PV \div \frac{1-(1+r)^{-time} }{rate} = C\\[/tex]
PV 851,082
time 14
rate 0.07
[tex]851081.87 \div \frac{1-(1+0.07)^{-14} }{0.07} = C\\[/tex]
C $ 97,316.904
Desing B
F0 251,000
operating and maintenance cost 89,000 for 14 years
[tex]C \times \frac{1-(1+r)^{-time} }{rate} = PV\\[/tex]
C 89,000.00
time 14
rate 0.07
[tex]89000 \times \frac{1-(1+0.07)^{-14} }{0.07} = PV\\[/tex]
PV $778,346.6507
net worth: $ 1,029,346.65
equivalent annual cost:
[tex]1029346.65 \div \frac{1-(1+0.07)^{-14} }{0.07} = C\\[/tex]
C $ 117,700.580