Take the statements below to be true, even if they differ from known facts. Which of the conclusions follow logically from them?
Statements:
1. No lemon is a sweet.
2. All lemons are fruits.
Conclusions:
I. All fruits are lemons.
II. Some fruits are not sweets.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Only conclusion II 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.
“No lemon is a sweet”: the circles of lemons and sweets do not touch
“All lemons are fruits”: the circle of lemons lies inside the circle of fruits; the other fruits may be sweets
Conclusion I: All fruits are lemons. — Does not follow. “All lemons are fruits” cannot be turned round; the fruits may be many more than the lemons, as in the diagram.
Conclusion II: Some fruits are not sweets. — Follows. The lemons are fruits, and no lemon is a sweet; so these fruits are not sweets.