Unplugged Practice Test: Logical Reasoning Set 3, Question 23 (Sufficient Assumption)
Taking the test? Finish it first. This page shows the answer.
- Sufficient Assumption questions ask for a premise that would guarantee the conclusion.
- Look for the choice that, once added, forces the conclusion. It often connects a term in the evidence to a term in the conclusion.
- Every question on this test is original, written to the same logical skeletons as real questions, and Steve checked every one himself before release.
The question
Okonkwo: The parks board adopted a strict limit on daily trailhead permits in March. A survey of 9 mountain districts shows, however, that limits of this kind drive up the price of guided trips and leave fewer side trails in usable repair. What follows is that keeping side trails usable is not one of the parks board's aims.
23. Which one of the following, if assumed, makes Okonkwo's conclusion follow logically?
- (A)The survey of permit limits was carried out by a firm with nothing to gain from its results.
- (B)Daily trailhead permits are not a proper matter for the parks board to decide.
- (C)Some board members who supported the limit will personally benefit from it.
- (D)The parks board occasionally acts on impulse and without reasoning things through.
- (E)The board members who supported the limit accept what the survey shows about limits of this kind.
EWhy (E) is correct
(E) supplies the missing link the conclusion needs. Okonkwo argues that keeping side trails usable isn't one of the board's aims, from the fact that the survey shows permit limits drive up trip prices and leave side trails in worse repair, and the board adopted the limit anyway. That only follows if the board members who backed the limit actually accept what the survey shows, since a board that adopted the limit without knowing its effects couldn't be said to have chosen against usable trails on purpose.
Why the other answers are wrong
AWhy (A) is wrong
(A) that the survey was done by a firm with nothing to gain supports the survey's credibility, but it doesn't connect the board's vote to what the board was trying to achieve.
BWhy (B) is wrong
(B) whether daily trailhead permits are even the board's business to decide is a question of jurisdiction, not of the board's aims.
CWhy (C) is wrong
(C) that some supporting members will personally benefit suggests a motive, but a motive to benefit doesn't prove usable trails weren't a goal.
DWhy (D) is wrong
(D) that the board sometimes acts on impulse says nothing about what it was after in this particular vote.
Common questions
What type of question is this?
Sufficient Assumption. Sufficient Assumption questions ask for a premise that would guarantee the conclusion.
How do I get better at Sufficient Assumption questions?
Look for the choice that, once added, forces the conclusion. It often connects a term in the evidence to a term in the conclusion. The free LSAT cheat sheet lists the wrong-answer patterns to watch for on every type.
