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Verbal Reasoning · Q90

Logical Deduction

Competitive Exams · Verbal Reasoning · question 90

Q90

Statements : Some dogs are rats. All rats are trees. Some trees are not dogs. Conclusions : I. Some trees are dogs. II. All dogs are trees. III. All rats are dogs. IV. No tree is dog.

A.
None follows
B.
Only I follows
Answer
C.
Only I and II follow
D.
Only II and III follow
E.
All follow

Answer: Option B

Solution

Answer: Option B
Solution:
Some dogs are rats. All rats are trees.

Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that 'Some dogs are trees'. I is the converse of this conclusion and so it holds.

All rats are trees. Some trees are not dogs.

Since the middle term 'trees' is not distributed even once in the premises, no definite conclusion follows.