LSAT Logic Reasoning 3 — Questions and Answers
Question 1: A law firm's memo states: 'Partners who bill over 2,000 hours annually receive bonuses. Associate Rivera billed 2,100 hours this year.' What can be properly concluded?
- Rivera will be promoted to partner.
- Rivera will receive a bonus. (Correct answer)
- Rivera billed more hours than any other associate.
- Rivera worked harder than the partners.
Correct answer: Rivera will receive a bonus.
The conditional 'if over 2,000 hours then bonus' combined with Rivera meeting that threshold directly yields the conclusion that Rivera receives a bonus.
Question 2: Which of the following is an example of an appeal to ignorance (argumentum ad ignorantiam)?
- No one has proven ghosts don't exist, so ghosts must exist. (Correct answer)
- Experts disagree on climate change, so the truth is somewhere in the middle.
- This policy worked in Canada, so it will work in the US.
- The majority of citizens support the law, so it must be just.
Correct answer: No one has proven ghosts don't exist, so ghosts must exist.
Concluding existence from lack of disproof is the classic appeal to ignorance fallacy.
Question 3: A study shows that people who eat breakfast daily have higher GPAs. A school counselor concludes students should eat breakfast to improve grades. Which assumption is the counselor making?
- GPA is the only measure of academic success.
- The correlation between breakfast and GPA is causal, not merely correlational. (Correct answer)
- All students currently skip breakfast.
- Breakfast foods contain nutrients proven to enhance memory.
Correct answer: The correlation between breakfast and GPA is causal, not merely correlational.
The counselor treats a correlational finding as causal, assuming breakfast eating produces higher GPAs rather than being merely associated with them.
Question 4: Premises: 'Either the defendant was at the scene or has an alibi. The defendant has no alibi.' The valid conclusion is:
- The defendant is guilty.
- The defendant was at the scene. (Correct answer)
- The defendant had motive.
- The defendant lied to police.
Correct answer: The defendant was at the scene.
This is a valid disjunctive syllogism: denying one disjunct (no alibi) forces acceptance of the other (was at the scene).
Question 5: An editorial argues that because violent video games are popular among teenagers, and teen violence has increased, violent games cause teen violence. The primary flaw in this reasoning is:
- It ignores that correlation does not establish causation. (Correct answer)
- It uses an appeal to authority by citing popularity.
- It commits a false dichotomy between games and other activities.
- It overgeneralizes from a single case study.
Correct answer: It ignores that correlation does not establish causation.
The argument mistakes a temporal or statistical correlation for a causal relationship without ruling out other explanations.
Question 6: Which principle, if established, would most justify the conclusion that a defendant who was legally insane at the time of a crime should not be criminally punished?
- Punishment should be proportional to the severity of the crime.
- Criminal liability requires the capacity to understand and conform to the law. (Correct answer)
- Rehabilitation is more effective than incarceration.
- Victims' rights take precedence over defendants' mental health claims.
Correct answer: Criminal liability requires the capacity to understand and conform to the law.
If liability requires the capacity to understand the law, then lacking that capacity (insanity) removes the basis for criminal punishment.
Question 7: The argument 'You can't trust Dr. Chen's research on sugar; she consumes a lot of soda' is an example of which fallacy?
- Straw man
- Ad hominem (tu quoque) (Correct answer)
- False equivalence
- Begging the question
Correct answer: Ad hominem (tu quoque)
Attacking the researcher's personal habits rather than her methodology or data is a tu quoque (you also do it) form of ad hominem.
LSAT Logic Reasoning 3
A law firm's memo states: 'Partners who bill over 2,000 hours annually receive bonuses.
Associate Rivera billed 2,100 hours this year.' What can be properly concluded?