Civil Service Verbal Reasoning Test Critical Reasoning and Logical Inference 1 — Questions and Answers
Question 1: All mammals are warm-blooded. Dolphins are mammals. Which conclusion MUST be true?
- Dolphins are warm-blooded (Correct answer)
- Dolphins are fish
- All warm-blooded animals are mammals
- Dolphins breathe air only
Correct answer: Dolphins are warm-blooded
This is a valid syllogism. If all mammals are warm-blooded and dolphins are mammals, then dolphins must be warm-blooded.
Question 2: No students who failed the exam passed the course. James failed the exam. Which conclusion MUST be true?
- James did not pass the course (Correct answer)
- James will retake the exam
- James studied hard
- James failed because he didn't revise
Correct answer: James did not pass the course
The rule states no exam-failers passed the course. James failed the exam, so he must not have passed the course. This follows logically.
Question 3: If it rains, the match is cancelled. The match was not cancelled. Which conclusion is VALID?
- It did not rain (Correct answer)
- It rained
- The match was postponed
- The weather was uncertain
Correct answer: It did not rain
This uses the logical form of contrapositive: if P then Q; not Q, therefore not P. If rain causes cancellation and there was no cancellation, it did not rain.
Question 4: All the files in folder A are marked confidential. This file is not marked confidential. Which MUST be true?
- This file is not in folder A (Correct answer)
- This file is in folder B
- This file has been mislabelled
- This file is unimportant
Correct answer: This file is not in folder A
If all files in folder A are confidential, and this file is not confidential, it cannot be in folder A. The contrapositive is valid.
Question 5: A survey found that people who drink coffee daily score higher on alertness tests. The survey concludes coffee improves alertness. Which WEAKENS this conclusion?
- Alert people may be more likely to drink coffee, not the other way round (Correct answer)
- Coffee is widely consumed worldwide
- The alertness tests were conducted in the morning
- Survey participants were volunteers
Correct answer: Alert people may be more likely to drink coffee, not the other way round
The conclusion assumes coffee causes alertness, but the relationship could be reversed — alert people may choose to drink coffee. This is the reverse causation flaw.
Question 6: Every employee who completed the training received a certificate. Sarah received a certificate. Which CANNOT be concluded?
- Sarah completed the training (Correct answer)
- Sarah is a good employee
- Sarah received recognition
- Sarah has a certificate
Correct answer: Sarah completed the training
The rule says completing training leads to a certificate — but others may also receive certificates. Sarah having a certificate does not prove she completed the training. This affirms the consequent fallacy.
Civil Service Verbal Reasoning Test Critical Reasoning and Logical Inference 1
All mammals are warm-blooded.
Dolphins are mammals.
Which conclusion MUST be true?