In each question below are given three statements followed by four conclusions numbered I, II, III and IV. You have to take the three 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 three given statements, disregarding commonly known facts.
Statements: All teachers are doctors. All doctors are engineers. All engineers are typists.
Conclusions:
I. Some typists are teachers.
II. All doctors are typists.
III. Some engineers are teachers.
IV. All doctors are teachers.
We know: All teachers are doctors. All doctors are engineers. All engineers are typists.
Now, we shall test each option by finding a scenario where the conclusion would not hold true. One which shall hold true in all the cases shall be valid in nature.
1. It is clear that all teachers are typists, because of the given data. Hence, we can conclude that some typists must be teachers.
2. This is a valid conclusion by the same logic as Option 1.
3. Since all doctors are engineers, some engineers shall definitely be doctors. This is a valid conclusion.
4. We only know that all teachers are doctors, but we cannot say vice versa. It might be possible that there are doctors that cannot be classified as teachers. Hence, an invalid conclusion.