In: Finance
1. A contractor needs water at a remote construction site for a five year project. A pipeline from a river,six miles away, will supply the water. The cost of the pipeline and the cost of pumping the water will vary with pipe size. See table below. The contractor uses a MARR of 7%. The contractor plans to work 2000 hours per year, and that is the time the pump will run each year. At the end of five years the salvage value of the pipeline will equal the cost of its demolition. | ||||||||||
Part A. (20 points) Which pipe diameter should she select? [Copy pertinent values before you start Part B. | ||||||||||
Part B. (5 points) The contractor may work overtime, so the work year has more than 2000 hours. How many hours must they work so that the costs of the 3 inch and 4 inch options are equal? | ||||||||||
Pipe Diameter | ||||||||||
2 inch | 3 inch | 4 inch | 6 inch | |||||||
Cost of pipeline and pump | $22,000.00 | $23,000.00 | $25,000.00 | $30,000.00 | ||||||
Cost per hour for pumping ($/hr) | $1.20 | $0.65 | $0.50 | $0.40 |
PART A
Annuity factor of 7% for 5 Years = [1-(1+r)^-n] / r = (1-(1+0.07)^-5) / 0.07 = 4.100197436
Calculation of PV of Cash outflow for all Pipe diameter
Annuity factor/Muliplier | 2 inch | 3 inch | 4 inch | 6 inch | |
Cost of pipeline and pump | 1 | 22000 | 23000 | 25000 | 30000 |
Cost per hour for pumping ($/hr) | 4.100197436 | 9840.473846 | 5330.256667 | 4100.197436 | 3280.157949 |
(1.2*2000*4.100197436) | (0.65*2000*4.100197436) | (0.5*2000*4.100197436) | (0.4*2000*4.100197436) | ||
Total | 31840.47385 | 28330.25667 | 29100.19744 | 33280.15795 |
As per the above table since PV of 3 inch diameter is the least of all the pipes therefore 3 inch pipe diameter should be selected
Part B
Difference in Fixed Cost of 3 inch and 4 inch pipe = 25000 - 23000 = $2000
Difference in cost per hour for pumping = $0.65 - $0.50 = $0.15
Total per hour cost for pumping for 5 years at PV = 0.15 * 4.10019744 = $0.615029615
Therefore Total hours per year required = DIff in fixed cost/Total per hour cost for pumping for 5 years at PV = 2000/0.615029615 = 3251.875926 hours per year
Therefore the contractor must work for 3251.875926 hours per year so that the cost of 3 inch & 4 inch pipe are equal