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Welleby’s Plan

The water In the underground water table beneath the town of Welleby is moderately saline— 20,000millkjrarns of salt per liter of water (mg/L), or roughly half as saline as ocean water. To lower the level of the water table and thus prevent agricultural land from being inundated with salt water, the town plans to pump water from the table at a rate of 450kiloliters per day (kL/day) into a large shallow pond, allowing much of the water to evaporate. The town plans to divert 10percent of the water pumped from the water table to supplement Us supply of drinking water, which Is currently piped In from great distances. Due to the water's supply, the town intends to construct a desalination plant to treat the diverted water for use as drinking water.

Desalination Types

Comparison

Welleby is deciding among the following three desalination methods.

Reverse Osmosis (RO): Water Is pushed through a membrane, leaving salts behind. RO systems can handle a large range of water flow rates and use relatively little energy. However, RO membranes are expensive and must be replaced every 2 to 5 years. There is also a possibility that bacteria can grow on the membrane. Introducing tastes and odors Into the desalinated water.

Multi-Effect Distillation (MED): Saline water Is heated to produce water vapor, from which Is condensed potable fresh water. This process requires large amounts of energy, regardless of the salinity of the source water. It becomes more cost effective as water volumes increase.

Electrodialysis (ED): Electricity is used to selectively move salts through a membrane. Consumption of energy Is directly proportional to the salinity of the water to be treated, so with higher salinities the process rapidly becomes more costly than other methods. ED membranes need to be replaced every 7 to 10years.

Based on the information provided, which one of the following benefits to Welleby is most likely to result from Its building a desalination plant?

West River Glen is deciding which network architecture should replace its old copper telephone lines. The town will replace 300 miles of Outside Plant (OSP) cable that will serve approximately 2,500 homes.

The first option is to install a Fiber to the Home (FTTH) system architecture that uses fiber-optic cable to transmit signals from the source to each home. The advantages of this architecture include greater bandwidth capabilities, less signal loss, and slightly lower new-cable deployment costs than the second option, Hybrid Fiber-Coax (HFC).

An HFC network integrates fiber-optic cables and devices with coaxial cables.

This will cost the town substantially less money for internal equipment and for customer installations. However, the coaxial cable does not last as long as fiberoptic cable and will thus need to be replaced more frequently, resulting in higher long-term maintenance expenses.

The town believes that either the FTTH or HFC architectures will be capable of serving the communities' data and television needs for the next 30 years.

For each of the following statements, select Yes if the statement can be inferred to be true on the basis of the information provided. Otherwise, select No.

Pete made a trip to the beach, of which 80 kilometers were on highway X. What was Pete’s average speed for the trip?

(1)

Pete’s average speed for the part of the trip on highway X was 80 kilometers per hour.

(2)

Pete’s average speed for the part of the trip not on highway X was 96 kilometers per hour.