LSAT 28, Logical Reasoning I, Q26, LSATHacks

QUESTION TEXT: Modern navigation systems, which are found in…

QUESTION TYPE: Strengthen – Exception

CONCLUSION: Aircraft navigation systems are under threat from the electronic devices we bring on board.

REASONING: On a recent flight, an airplane went off course when passenger turned on his laptop. The airplane’s dials dimmed.

Modern navigation systems are more vulnerable to interference than old vacuum tube systems. Aircraft need these systems to receive radio signals from airports, among other things.

ANALYSIS: We’re not told how electronic devices can cause problems. It could just be a coincidence that the plane had trouble when the laptop was turned on.

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1. This supports the idea that the laptop caused the interference. It wasn’t just a coincidence.
2. This shows that all electronic devices we bring on board could interfere with navigation circuitry.
3. This isn’t conclusive, but it supports the idea that electronic devices are a problem. There have been no problems when the proposed cause (the devices) was absent.
4. This shows that radiation from electronic devices can travel far enough to interfere with navigation systems.
5. CORRECT. This shows the two things started together. But it doesn’t show that electronic devices actually are the cause. Maybe it’s all just a coincidence.

   As an example, electronic file sharing became popular about the same time as laptops. Maybe music piracy caused the problems with navigation systems?

   The fact that two things happen together doesn’t mean that one causes the other.

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