Q. Statement-1 : Some doctors are teachers.
Statement-2 : All teachers are engineers
Statement-3 : All engineers are scientists.
Conclusion-I : Some scientists are doctors.
Conclusion-II : All engineers are doctors.
Conclusion-III : Some engineers are doctors.
Which one of the following is correct?
a. Only Conclusion-I
b. Only Conclusion-II
c. Both Conclusion-I and Conclusion-III
d. Both Conclusion-I and Conclusion-II
Correct Answer: c. Both Conclusion-I and Conclusion-III
Question from UPSC Prelims 2022 CSAT Paper
Explanation :
From Statement-1 we know that some doctors are teachers.
From Statement-2 we know that all teachers are engineers.
Combining these two statements we can conclude that some doctors are engineers.
From Statement-3 we know that all engineers are scientists.
Therefore, combining this with the previous conclusion, we can conclude that some scientists are doctors (Conclusion-I).
Since only some doctors are engineers (not all), Conclusion-II is incorrect. However, since some doctors are engineers, Conclusion-III is correct.
