Answer:
Step-by-step explanation:
a) Present worth of the system:
First step :
Calculation of bank installment:
We are given:
·nitial costs = $32,000
Borrow amount = ½ of purchase price
Payment of borrow amount = EOY 2 to EOY 4 (3 Equal installments)
Bank loan interest = 8.5% = 8.5/100 = 0.085
Assume the installment amount is F. They will be paid at end of year 2 to end of year 4. Their present value must be equal to borrow amount.
Present value of cost to be incurred in future can be calculated by below formula:
F P (1 + i)
F= Future cost
i = Rate of interest
n = time (in years)
Therefore,
F F $32,000 2 F (1 +0.085)2 (1 +0.085) 3 (1 +0.085) + +
.: 2.35394F = 16,000 or F = 16,000 2.35394 - $6,797.11
Step 2: Present worth of the system:
Given Data:
Initial costs = $32,000
Expected life = 7 years
Salvage value = $5,000
O&M Costs = $2,000 per year
MARR = 12.5%
= 12.5/100
= 0.125
Present value of uniform recurring payments is given by below formula:
P=A (1 + i) - 1 i(1+i)n 72
Where,
P = Present Value
A = Recurring payments per annum
i = rate of interest
n = time (in years)
Hence present value of O&M costs,
P1 = -2,000 x (1 + 0.125) 7-1 0.125 x (1 + 0.125) 7 -$8,984.60
Present worth of the system calculated in below table:
Description
F ($)
MARR (i)
per year
n (years)
P ($)
Initial investment (1/2 of purchase price)
-16,000.00
0.125
0
-16,000.00
Bank installment EOY2
-6,797.11
0.125
2
-5,370.56
Bank installment EOY3
-6,797.11
0.125
3
-4,773.83
Bank installment EOY4
-6,797.11
0.125
4
-4,243.40
Salvage value
5,000.00
0.125
7
2,192.31
O&M Costs
-8,984.60
0.125
0
-8,984.60
The current worth of the new system
-37,180.07
Part b) Decision rule of judgment:
Assuming current value of costs is lower than current value of benefit, an alternative is known to be economic to use based on current worth analysis.
Part c) Decision for the water filtration system:
Given Data:
· Annual savings from filtration system (A) = $13,000 per year
· Expected life (n) = 7 years
· MARR = 12.5%
= 12.5/100
= 0.125
Present value of benefits = 13,000 X (1 + 0.125)7 - 1 0.125 x (1 + 0.125) 7 $58,399.91
Since current value of costs is less than current value of benefit, this is an worthwhile system and has to be be purchased.