Logical ReasoningDifficulty: Medium

PT106 S1 Q26 Explanation

Modern navigation systems, which

A free, expert breakdown of this official LSAT Logical Reasoning question.

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Stimulus

Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes. During landing, navigation systems receive radio signals from the airport to guide the plane to the runway. Recently, one plane with the electronic devices that passengers carry on board, such as cassette players and laptop computers.

What this question is testing

Strengthen

Your task

Find the choice that makes the argument's conclusion more likely to be true.

Common trap

Answers that are consistent with the argument but add no real support, or that strengthen a claim the argument doesn't make.

Winning move

Locate the gap between evidence and conclusion, then pick the choice that closes it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
26.

Which one of the following, if true, LEAST strengthens the

Answer choices

  1. Strengthens3% picked this

    After the laptop computer was turned off, the plane regained course and its navigation instruments and

    After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal. This directly supports the causal claim that the electronic device was interfering with navigational equipment in classic "No Cause, No Effect" form. When the laptop wasn't open, there wasn't interference messing up the plane.

  2. Strengthens6% picked this

    When in use all electronic devices emit electromagnetic radiation, which is known to

    When in use, all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry. This helps make it more plausible that passenger devices could cause the relevant type of interference that would mess with the airplanes. This statement provides a mechanism—electromagnetic radiation—for why electronic devices might interfere with low-power circuitry.

  3. Strengthens6% picked this

    No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned

    This indicates that the interference occurs only when electronic devices are present, supporting the causal link between these devices and navigation issues, in classic "No Cause, No Effect" fashion. On planes that don't have the passenger devices, we don't have the planes' instruments glitching out.

  4. Strengthens6% picked this

    Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within

    Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems. This highlights the proximity of potentially interfering sources (passenger devices) to navigation systems, supporting the argument's case. It rules out a potential objection like, "Wouldn't the passenger's laptop be too far away from the instruments in the cockpit to mess them up?"

  5. Correct79% picked this

    Planes were first equipped with low-power circuitry at about the same time portable electronic

    Why this is right

    Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular. This fact might suggest a correlation, but it doesn't provide evidence supporting the causal claim that the electronic devices are responsible for interference. Correlation in timing doesn't necessarily imply causation for the navigational issues.

    Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

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