From the evil geniuses at Manhattan GMAT, try this interesting CR question, the read the explanation below!

Scientists recently documented that influenza spreads around the world more efficiently in the modern era due to commercial air travel. Symptoms of a pandemic-level flu are severe enough that the ill would likely cancel or reschedule air travel, but an infected person can travel across the globe before the first signs appear. Further, if symptoms develop while someone is still on a plane, the infected person’s cough can spread the virus easily in the enclosed and closely packed environment.

Which of the following would best minimize the role air travel can play in the spread of influenza during a pandemic?

(A) installing air filtration systems in the planes to kill any flu virus particles flowing through the filters
(B) requiring air travelers to receive flu vaccinations far enough in advance of the trip to provide protection against the disease
(C) refusing to allow children, the elderly, or others who are especially vulnerable to flu to travel by air during a pandemic
(D) requiring all air travelers to wash their hands before boarding a plane
(E) conducting medical examinations during the boarding process to weed out passengers with flu symptoms

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Explanation:

Conclusion: Influenza spreads more rapidly b/c of airplanes.

Evidence: Infected person can travel before symptoms appear & spread illness

Question Rephrase: How could air travel stop the spread of disease?

Prediction: If there was a way to make sure people who boarded were not ill, or if there was a way they couldn’t spread it once on the plane.

A – Yes, this stops the spread on the plane, but could still let the ill people fly
B – Yes, this stops the ill people from flying
C – No, this only stops certain ill people from flying
D – No, hand washing doesn’t prevent those already ill from flying
E – No, the passage states that people can travel before “first signs appear” so the examinations would likely be ineffective

Between A and B, my choice would be B since it prevents the ill from flying altogether and would therefore “best minimize.”

Remember that the correct answer is going to be the one based on the information from the passage. The passage only gave 2 pieces of evidence: (1) sick people travel before symptoms, and (2) sick people spread illness within the cabin.

Repeated vaccinations and whether a person would reschedule/cancel travel are two issues that are not mentioned and are entirely outside the scope of the passage. Be careful not to use outside information. Follow the logic of the passage.