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 sparrows are flyers.
2. No sparrow is an eagle.
Conclusions:
I. No flyer is an eagle.
II. Some flyers are eagles.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Either conclusion I or conclusion II follows
When two conclusions do not follow on their own, but in every diagram exactly one of them is true (such as “some X are Y” and “no X is Y”), the answer is “either one or the other follows”.
“All sparrows are flyers”: the circle of sparrows lies inside the circle of flyers
“No sparrow is an eagle”: the circles of sparrows and eagles do not touch; the flyers that are not sparrows may or may not be eagles
Conclusion I: No flyer is an eagle. — Does not follow on its own. In case 2 some flyers (not sparrows) are eagles, so it is false there.
Conclusion II: Some flyers are eagles. — Does not follow on its own. In case 1 the flyers and eagles do not meet, so it is false there.
Flyers and eagles either meet or they do not; there is no third case. So in every diagram exactly one of I and II is true: either conclusion I or conclusion II follows.