Which of the following statements are so related that if one of them is false, the other must be true, even though both of them can be true? Choose the correct answer from the options given below.
1.Some cars are e-vehicles
2.Some cars are not e-vehicles
3.No cars are e-vehicles
4.All cars are e-vehicles
A1 and 2 only ✓ Correct
B2 and 3 only
C1 and 3 only
D3 and 4 only
Correct answer: (A) 1 and 2 only
Explanation
Some cars are e-vehicles and some cars are not e-vehicles are subcontraries, so statements 1 and 2 satisfy the condition.
Subcontraries cannot both be false yet can both be true, exactly the relation stated.
Statement 1 is the particular affirmative I proposition.
Statement 2 is the particular negative O proposition.
No cars are e-vehicles (item 3) and all cars are e-vehicles (item 4) are contraries, which can both be false.
The square of opposition sets out contrary, subcontrary, contradictory and subaltern relations.
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