Unplugged Practice Test: Logical Reasoning Set 1, Question 17 (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
Seeking to trim production costs and so widen her company's margins, Ms. Delacroix eliminated the thermal cutoff switch from the space heaters her firm sells. Whatever the regulations may have permitted, her decision was plainly wrong. She has designed heating appliances for 20 years, so she surely grasped that a heater without that switch would leave households facing a grave hazard.
17. The argument's conclusion is properly drawn if which one of the following is assumed?
- (A)Anyone who has designed heating appliances for 20 years would grasp that a heater stripped of its thermal cutoff switch leaves households facing a grave hazard.
- (B)Deliberately leaving people to face a grave hazard in order to increase earnings is wrong.
- (C)An act that violates no regulation can still be wrong.
- (D)Ms. Delacroix's firm took in large earnings from sales of the redesigned heater.
- (E)Ms. Delacroix either grasped, or was in a position to grasp, that a heater lacking the thermal cutoff switch would leave households facing a grave hazard.
BWhy (B) is correct
The argument moves from Delacroix knowingly leaving households facing a grave hazard so she could widen her firm's margins to the claim that her decision was plainly wrong, and only a moral rule connecting the two can carry that weight. (B) states it. If deliberately leaving people to face a grave hazard in order to increase earnings is wrong, then Delacroix, who stripped the thermal cutoff switch to trim costs while grasping the danger, acted wrongly. That closes the gap.
Why the other answers are wrong
AWhy (A) is wrong
(A) confirms that a 20-year designer would grasp the danger, which supports her knowledge but never says that knowingly creating danger is wrong.
CWhy (C) is wrong
(C) covers the "whatever the regulations may have permitted" aside but doesn't establish that this particular decision was wrong.
DWhy (D) is wrong
(D) adds a fact about earnings that isn't needed and doesn't turn a dangerous act into a wrong one on its own.
EWhy (E) is wrong
(E) restates that she grasped or was in a position to grasp the hazard, which is knowledge again, not the missing moral rule.
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.
