Question

Statements: No house is school. All colleges are schools. All schools are teachers.
Conclusions:
I. No house is teacher.
II. All colleges are teachers.
III. Some teachers are not houses.
IV. No college is house.

• A. None follows
• B. Only either I or IV follows
• C. Only II, III and IV follow
• D. All follow
• E. Only either I or IV, and III follow

Answer 1

Answer: (C)

Only II, III and IV follow

All colleges are schools. No house is school.
Since both the premises are universal and one premise is negative, the conclusion must be universal negative and should not contain the middle term. So, it follows that 'No college is house'. Thus, IV follows.
All colleges are schools. All schools are teachers.
Clearly, it follows that 'All colleges are teachers'. Thus, II follows.
No house is school. All schools are teachers.
Since the middle term 'schools' is distributed twice, the conclusion must be particular.
Since one premise is negative, the conclusion must be negative. So, it follows that 'Some teachers are not houses'.