Question

In each of the questions below are given four statements followed by three conclusions numbered I, II & Ill. You have to take the given statements to be true even if they seem to be at variance from commonly known facts. Read all the conclusions and then decide which of the given conclusions logically follows from the given statements disregarding commonly known facts.

Statements
Some fish are crocodiles.
Some crocodiles are snakes.
No snake is a tortoise.
All tortoises are frogs.

Conclusions
I. No snake is a frog.
II. Some snakes are fish.
III. Some fish are frogs.

• A. None follows
• B. Only I & II follow
• C. Only II & III follow
• D. Only I & III follow
• E. None of these

Answer 1

The correct option is A None follows

The first and second premises are particular affirmative (I-type).
The third premise is universal negative (E-type).
The fourth premise is universal affirmative (A-type).
Some crocodiles are snakes.
No snake is a tortoise.
$I+E\Rightarrow O$-type conclusion.
Some crocodiles are not tortoises.
No snake is a tortoise.
All tortoises are frogs.
$E+A=O_1$-type conclusion.
Some frogs are not snakes.