Crossover Aptitude Test Logical Reasoning: Syllogisms 3

Question 1

Statement 1: All cars are vehicles. Statement 2: All vehicles need fuel. Conclusion: All cars need fuel. Is the conclusion:

Accepted Answer

True

Answer

Both premises are universal affirmatives, so the conclusion that all cars need fuel necessarily follows.

Question 2

Some athletes are vegetarians. All vegetarians avoid meat. Which is definitely true?

Accepted Answer

Some athletes avoid meat.

Answer

The athletes who are vegetarians must avoid meat, so some athletes avoid meat.

Question 3

No mammals are cold-blooded. All fish are cold-blooded. Therefore:

Accepted Answer

No fish are mammals.

Answer

Mammals cannot be cold-blooded, and fish must be cold-blooded, so the two groups cannot overlap.

Question 4

All P are Q. Some Q are R. Which conclusion is INVALID?

Accepted Answer

All P are R.

Answer

We cannot conclude all P are R because only some Q (which contains P) are R.

Question 5

All honest people keep promises. John does not keep promises. Therefore:

Accepted Answer

John is not honest.

Answer

By contrapositive, if someone doesn't keep promises, they are not honest.

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