- PowerScore Staff
- Posts: 6043
- Joined: Mar 25, 2011
- Sat Apr 08, 2017 10:58 am
#33981
Must Be True - SN. The correct answer choice is (E).
This is a classic Conditional Reasoning and Must Be True combination problem. Let's start by breaking down the stimulus:
C 
IR
This occurs because each sufficient condition relies on a necessary condition, and those two necessary conditions are opposite of each other (and thus cannot exist simultaneously). Imagine if the two statements were instead: To go to dinner we must be rich and to go to the movies we must be poor. If those two statements are true, then no one can go to both a dinner and a movie (and we'll ignore the time sequence aspect here and assume no one loses their fortune in between dinner and a movie
).
Given the above analysis, we can attack the answer choices:
Answer choice (A): While this answer might make some sense in the real world, there is no justification for the statement base don what is in the stimulus.
Answer choice (B): While the two are mutually exclusive and cannot both be achieved, there is no indication from the stimulus that one of them can't be achieved.
Answer choice (C): Again, there is no evidence to support this statement.
Answer choice (D): This is a Mistaken Negation of the statement in the third sentence, and is thus incorrect.
Answer choice (E): This is the correct answer. This reflects the inference drawn from combining the second and third sentences, and is a variation on the expected answer (that CE and IR cannot coexist).
This is a classic Conditional Reasoning and Must Be True combination problem. Let's start by breaking down the stimulus:
- The first sentence provides background information about efficiency and redundancy: they are contradictory but can be used together in communications.
The next two sentences present conditional statements:
(2): CE
EPU
(Completely efficient every permutation understandable)
(3) IR EPU
(Imperfect receptor every permutation not understandable)
C IRThis occurs because each sufficient condition relies on a necessary condition, and those two necessary conditions are opposite of each other (and thus cannot exist simultaneously). Imagine if the two statements were instead: To go to dinner we must be rich and to go to the movies we must be poor. If those two statements are true, then no one can go to both a dinner and a movie (and we'll ignore the time sequence aspect here and assume no one loses their fortune in between dinner and a movie
). Given the above analysis, we can attack the answer choices:
Answer choice (A): While this answer might make some sense in the real world, there is no justification for the statement base don what is in the stimulus.
Answer choice (B): While the two are mutually exclusive and cannot both be achieved, there is no indication from the stimulus that one of them can't be achieved.
Answer choice (C): Again, there is no evidence to support this statement.
Answer choice (D): This is a Mistaken Negation of the statement in the third sentence, and is thus incorrect.
Answer choice (E): This is the correct answer. This reflects the inference drawn from combining the second and third sentences, and is a variation on the expected answer (that CE and IR cannot coexist).
Dave Killoran
PowerScore Test Preparation
Follow me on X/Twitter at http://twitter.com/DaveKilloran
My LSAT Articles: http://blog.powerscore.com/lsat/author/dave-killoran
PowerScore Podcast: http://www.powerscore.com/lsat/podcast/
PowerScore Test Preparation
Follow me on X/Twitter at http://twitter.com/DaveKilloran
My LSAT Articles: http://blog.powerscore.com/lsat/author/dave-killoran
PowerScore Podcast: http://www.powerscore.com/lsat/podcast/
