Logical Reasoning - Logical Deduction - Discussion
In each of the following questions, three statements are given followed by four conclusions numbered I, II, III and TV. You have to take the given statements to be true even if they seem to be at variance with commonly known facts and then decide which of the given conclusions logically follows from the given statements disregarding commonly known facts.
Statements: No house is school. All colleges are schools. All schools are teachers.
Conclusions:
- No house is teacher.
- All colleges are teachers.
- Some teachers are not houses.
- No college is house.
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'.
It should be all follows.
Statement:
No house is school.
All schools are teachers.(All teachers are schools - reversed statement)
Therefore:
If,
No house is school.
All teachers are in schools.
Then, No house is a teacher. Is a correct statement that follows.
Statement :
No house is school.
All schools are teachers.
Ans: No house is a teacher. (subject and the predicate is same here, so it gets canceled).
Could you please make me clear why this answer was not right?