GCAT Syllogistic Reasoning 5

Question 1

No mammals lay eggs. Platypuses lay eggs. What must follow?

Accepted Answer

Platypuses are not mammals.

Answer

By contrapositive, if something lays eggs it cannot be a mammal.

Question 2

All optimists are happy. All happy people sleep well. Some night-shift workers do not sleep well. Which follows?

Accepted Answer

Some night-shift workers are not optimists.

Answer

Optimists → happy → sleep well; those who don't sleep well are not happy, hence not optimists — applying to the night-shift workers who don't sleep well.

Question 3

All P are Q. No R are Q. Some S are R. Which is valid?

Accepted Answer

Some S are not Q.

Answer

The S that are R are not Q (since no R are Q), so at least some S are not Q.

Question 4

Some teachers are strict. All strict people demand discipline. Which must be true?

Accepted Answer

Some teachers demand discipline.

Answer

Strict teachers must demand discipline, so at least some teachers demand discipline.

Question 5

All carnivores eat meat. This creature does not eat meat. Which conclusion is valid?

Accepted Answer

This creature is not a carnivore.

Answer

Contrapositive of 'all carnivores eat meat' is 'not eating meat means not a carnivore.'

GCAT - General Cognitive Ability Test Practice Test

GCAT - General Cognitive Ability Test Practice Test

GCAT Syllogistic Reasoning 5