Gastrointestinal illnesses can be contracted from swimming in the ocean when the bacteria responsible for these illnesses are present in the water. However, tests designed to detect the presence of these bacteria are unreliable when used to monitor water at beaches. Public health officials therefore plan to stop using these tests and instead to begin using other tests which, although highly reliable, test only for the presence of certain harmless bacteria.
Which of the following, if true, best justifies the health officials' testing policy?
A. The bacteria that cause gastrointestinal illnesses are typically present in water only when the bacteria for which the health officials will test are also present
B. Reliable tests for the harmless bacteria have only recently become available.
C. Tests for the harmless bacteria are less expensive and faster to run than are the tests designed to detect the bacteria that cause gastrointestinal illnesses.
D. Few people who become infected with the bacteria that cause gastrointestinal illnesses also harbor the harmless bacteria for which health officials test beach water.
E. It is safer for those performing the tests to test water at beaches for the presence of the harmless bacteria rather than for the presence of bacteria that cause gastrointestinal illnesses.
The Kalladian Labor Statistics Bureau keeps track of wage rates in 25 foreign countries. In one of these countries, Ellmark, hourly wages for manufacturing workers declined last year by 31 percent, calculated in Kalladian florins; no other country registered as large a decline. In Ellmark last year, however, hourly wages for manufacturing workers actually increased in terms of Ellmark’ national currency.
If the statements above are true, which of the following must also be true?
A. In terms of the national currency of Ellmark, hourly wages for manufacturing workers in Kalladia declined last year.
B. Last year, in none of the 25 countries did hourly wages for manufacturing workers increase in terms of the Kalladian florin
C. In Ellmark last year, hourly wages for workers not in manufacturing declined in terms of Ellmark’s national currency.
D. Last year, hourly wages for manufacturing workers in each of the 25 countries increased in terms of their respective national currencies.
E. The value of Ellmark’s national currency decreased relative to that of the Kalladian florin.
