Take the statements below to be true, even if they differ from known facts. Which of the conclusions follow logically from them?
Statements:
1. All pilots are swimmers.
2. All pilots are runners.
Conclusions:
I. Some swimmers are runners.
II. All runners are swimmers.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Only conclusion I follows
A conclusion follows only if it is true in every diagram that fits the statements; each class named in a statement is taken to have members.
“All pilots are swimmers”: the circle of pilots lies inside the circle of swimmers
“All pilots are runners”: the circle of pilots also lies inside the circle of runners, so swimmers and runners must meet at least where the pilots are
Conclusion I: Some swimmers are runners. — Follows. The pilots are swimmers and also runners, so at least the pilots are swimmers who are runners.
Conclusion II: All runners are swimmers. — Does not follow. Only the pilots are sure to be swimmers; the other runners may lie outside the swimmers, as in the diagram.