## Question

2. You have a system in which a colleague intends to install the pump described by the pump curve in Figure 1 using an 8” impeller into a system which is designed to pump water at roughly 25 °C from a cooling pond back into a cooling water holding tank in your plant. The goal is to have a system that can deliver at least 500 gpm of water to the tank. The elevation rise from the surface of the cooling pond to the centerline of the suction inlet of the pump is 4 feet and the suction line is 4 inches inside diameter commercial steel and 50 feet long. The elevation rise from the centerline of the suction inlet of the pump to the top of the cooling water holding tank where the water will be allowed to free flow into the top of the tank is an additional 36 feet. The discharge line from the pump is 3 inches inside diameter commercial steel and is 200 feet long in total and contains one sharp 90 degree elbow where it turns to rise up the side of the holding tank. Answer the following questions to determine if the system will work as required:

a. At what flow rate will water be pumped to the holding tank if this pump is used in the system?

b. What power motor must be used?

c. What is the NPSHA in this case and does it satisfy the needs of the pump?

d. Will this pump work as desired in this design?

3. You have a choice between two pump systems. Pump #1 costs $15,000 to buy initially, is expected to need $2500 worth of service at the end of every 3 years, will have an annual utilities cost of $2000, and is expected to have a 12 year lifetime. Pump #2 costs $20,000 to buy initially, is expected to need $2500 worth of service at the end of every 4 years, will have an annual utilities cost of $1900, and is expected to have a 12 year lifetime. If you assume no inflation and an annual effective interest rate of 15% (equivalent to a required 15% rate of return), which pump should you buy?

4. You want to analyze your retirement planning process. Analyze the net present value and the future value at age 65 of the following cases assuming that you will stop contributing to your retirement funds at age 65:

a. You finish college at age 22, get a job earning $65,000 per year and you save 10% of your salary each year from age 22 until age 65. Assume your salary increases at an average rate of 2% per year, that inflation is roughly 2% per year, and that your investments make an annual average interest rate return of 8%.

b. You finish college at age 22, get a job earning $65,000 per year and you save 10% of your salary each year from age 32 until age 65. Assume your salary increases at an average rate of 2% per year, that inflation is roughly 2% per year, and that your investments make an annual average interest rate return of 8%.

c. You finish college at age 22, get a job earning $65,000 per year and you save 10% of your salary each year from age 42 until age 65. Assume your salary increases at an average rate of 2% per year, that inflation is roughly 2% per year, and that your investments make an annual average interest rate return of 8%.

d. You finish college at age 22, get a job earning $65,000 per year and you save 10% of your salary each year from age 22 until age 65. Assume your salary increases at an average rate of 2% per year, that inflation is roughly 2% per year, and that your investments make an annual average interest rate return of 10%.

e. You finish college at age 22, get a job earning $65,000 per year and you save 5% of your salary each year from age 22 until age 65. Assume your salary increases at an average rate of 2% per year, that inflation is roughly 2% per year, and that your investments make an annual average interest rate return of 8%.

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