HAST Logical Reasoning

Question 1

All mammals are warm-blooded. All dogs are mammals. What conclusion must be true?

Accepted Answer

All dogs are warm-blooded

Answer

This is a valid syllogism: if all mammals are warm-blooded and all dogs are mammals, then all dogs must be warm-blooded.

Question 2

If it rains, the ground gets wet. The ground is not wet. What can you conclude?

Accepted Answer

It did not rain

Answer

This uses modus tollens: if the consequence (wet ground) is false, the cause (rain) must also be false.

Question 3

No reptiles are warm-blooded. A lizard is a reptile. Which statement is valid?

Accepted Answer

A lizard is not warm-blooded

Answer

Since no reptiles are warm-blooded and a lizard is a reptile, the lizard cannot be warm-blooded.

Question 4

Only students who study pass the exam. Maria passed the exam. What must be true?

Accepted Answer

Maria studied

Answer

If passing requires studying, and Maria passed, then Maria must have studied.

Question 5

In a sequence: every even number is followed by its half. Starting at 64, what is the fourth number?

Accepted Answer

8

Answer

64 → 32 → 16 → 8: each step halves the value, so the fourth number is 8.

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