Which of the following propositions are so related that they cannot both be…
2026
Which of the following propositions are so related that they cannot both be true although they may both be false?
A. All cars are vehicles.
B. Some cars are vehicles.
C. No cars are vehicles.
D. Some cars are not vehicles.
Choose the correct answer from the options given below:
- A.
A and D only
- B.
A and C only
- C.
C and D only
- D.
B and C only
Attempted by 60 students.
Show answer & explanation
Correct answer: B
This question tests the logical relationship known as contraries in the Square of Opposition.
Contrary propositions cannot both be true at the same time, although they can both be false.
This specific relationship applies to Universal Affirmative (A) and Universal Negative (E) propositions. Proposition A ('All cars are vehicles') is a Universal Affirmative, while Proposition C ('No cars are vehicles') is a Universal Negative. Thus, they cannot both be true.