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 vans are vehicles.
2. All trucks are vehicles.
3. Some trucks are imports.
Conclusions:
I. Some vans are imports.
II. Some vehicles are imports.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 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.
“All vans are vehicles”: the circle of vans lies inside the circle of vehicles
“All trucks are vehicles”: the circle of trucks also lies inside the circle of vehicles; vans and trucks need not meet
“Some trucks are imports”: the circles of trucks and imports overlap
Conclusion I: Some vans are imports. — Does not follow. The imports are linked only with the trucks, and the vans may be other vehicles; in the diagram vans and imports do not meet.
Conclusion II: Some vehicles are imports. — Follows. The trucks that are imports are vehicles too, because every truck is a vehicle.