The cause of the wreck of the ship Edmund Fitzgerald in a severe storm on Lake Superior is still unknown....

GMAT Critical Reasoning : (CR) Questions

Source: Official Guide

Critical Reasoning

Assumption

MEDIUM

...

Notes

Post a Query

The cause of the wreck of the ship Edmund Fitzgerald in a severe storm on Lake Superior is still unknown. When the sunken wreckage of the vessel was found, searchers discovered the hull in two pieces lying close together. The storm's violent waves would have caused separate pieces floating even briefly on the surface to drift apart. Therefore the breakup of the hull can be ruled out as the cause of the sinking.

Which of the following is an assumption on which the argument depends?

Ships as large as the Edmund rarely sink except in the most violent weather.

Underwater currents at the time of the storm did not move the separated pieces of the hull together again.

Pieces of the hull would have sunk more quickly than the intact hull would have.

The waves of the storm were not violent enough to have caused the ship to break up the surface.

If the ship broke up before sinking, the pieces of the hull would not have remained on the surface for very long.

Solution

Passage Analysis:

Text from Passage	Analysis
The cause of the wreck of the ship Edmund Fitzgerald in a severe storm on Lake Superior is still unknown.	What it says: We don't know why the Edmund Fitzgerald sank during a bad storm What it does: Sets up the mystery that the argument will try to solve What it is: Background information
When the sunken wreckage of the vessel was found, searchers discovered the hull in two pieces lying close together.	What it says: The ship's hull was found broken into two pieces that were near each other What it does: Provides key physical evidence about the wreck's condition What it is: Factual observation Visualization: Ship hull split into 2 pieces, both pieces located close together on lake bottom
The storm's violent waves would have caused separate pieces floating even briefly on the surface to drift apart.	What it says: Storm waves would push floating pieces away from each other What it does: Explains what normally happens to floating debris in storms What it is: General principle about storm behavior Visualization: Storm waves → floating pieces drift apart (maybe 100+ feet separation)
Therefore the breakup of the hull can be ruled out as the cause of the sinking.	What it says: The hull breaking apart didn't cause the ship to sink What it does: Draws the main conclusion by connecting the close location of pieces with storm wave behavior What it is: Author's conclusion

Argument Flow:

The argument starts with a mystery (unknown cause of sinking), then presents physical evidence (two hull pieces found close together), adds a general principle about storm behavior (waves separate floating debris), and concludes that hull breakup wasn't the cause of sinking.

Main Conclusion:

The breakup of the hull can be ruled out as the cause of the Edmund Fitzgerald's sinking.

Logical Structure:

The logic works like this: IF the hull broke apart while floating (causing the sinking), THEN the storm waves would have pushed the pieces far apart. BUT we found the pieces close together. THEREFORE, the hull must not have broken apart while floating, so hull breakup wasn't the cause of the sinking.

Prethinking:

Question type:

Assumption - We need to find what the argument takes for granted. An assumption is something that must be true for the conclusion to follow logically from the premises.

Precision of Claims

The argument makes specific claims about spatial relationships (pieces lying close together), timing (floating briefly), and causation (ruling out hull breakup as the cause). We need to focus on what gaps exist between the evidence and conclusion.

Strategy

For assumption questions, we identify ways the conclusion could be falsified while respecting the given facts. The argument concludes that hull breakup didn't cause the sinking because the pieces are close together and storm waves would drift floating pieces apart. We need to find what unstated beliefs this reasoning depends on.

Answer Choices Explained

Ships as large as the Edmund rarely sink except in the most violent weather.

This focuses on the general frequency of large ship sinkings, but our argument isn't about how often such ships sink or what weather conditions cause sinkings. The argument is specifically about ruling out hull breakup as the cause based on where the pieces were found. Whether large ships rarely sink except in violent weather doesn't affect the logic connecting piece location to the cause of sinking. This is outside the scope of our reasoning.

Underwater currents at the time of the storm did not move the separated pieces of the hull together again.

This directly plugs a critical logical gap in our argument. The argument reasons: pieces are close together → storm waves would separate floating pieces → therefore breakup didn't cause sinking. But what if the pieces did break apart and drift, then underwater currents brought them back together? The argument never considers this possibility, so it must assume this didn't happen. If underwater currents had moved separated pieces back together, finding them close wouldn't rule out surface breakup. The argument's conclusion depends on this assumption.

Pieces of the hull would have sunk more quickly than the intact hull would have.

This deals with sinking speed differences between broken and intact hulls, but our argument isn't about how quickly things sank. The argument focuses on the location where pieces were found and what that tells us about whether breakup occurred on the surface. The relative sinking speeds don't affect the logic about wave-caused drift patterns for floating debris.

The waves of the storm were not violent enough to have caused the ship to break up the surface.

This contradicts information already given in our argument. The argument explicitly states that 'the storm's violent waves would have caused separate pieces floating even briefly on the surface to drift apart.' The argument acknowledges the waves were violent enough to separate pieces, so this assumption about wave strength is inconsistent with the argument's own premises.

If the ship broke up before sinking, the pieces of the hull would not have remained on the surface for very long.

This addresses how long pieces would float, but our argument already accounts for brief surface time by saying waves would cause separation 'even briefly.' The argument's logic doesn't depend on the exact duration pieces stayed afloat - it depends on the assumption that during whatever time they were floating, waves would separate them and nothing would bring them back together.

Rate this Solution

Tell us what you think about this solution

...

Forum Discussions

Start a new discussion

Post

Previous Attempts

Loading attempts...