Difficulty: Medium
Correct Answer: Only conclusion I follows
Explanation:
Introduction / Context:
This problem is a classic example of a syllogism based on categorical statements. We are given two statements about the relationship between bikes, two wheelers, and wheels, and then we are asked to judge which conclusion follows logically. The key idea is to ignore real world knowledge and work only with the abstract logic of sets. Visualizing the sets as circles in a Venn diagram is very helpful for such questions.
Given Data / Assumptions:
- Statement I: No bikes are two wheelers, so the set of bikes and the set of two wheelers are completely disjoint.
- Statement II: All wheels are bikes, so the set of wheels lies entirely inside the set of bikes.
- Conclusions compare the sets wheels and two wheelers using the information from the two statements.
Concept / Approach:
We interpret the statements in terms of set relationships. "No A are B" means A and B do not overlap at all. "All A are B" means the entire set A lies inside set B. If a third set is inside one of these sets, its relationship with the other set can be derived by transitivity of inclusion or exclusion. We then test each conclusion separately and see whether it must be true in every possible diagram that satisfies the two given statements.
Step-by-Step Solution:
Step 1: Represent bikes as set B, two wheelers as set T, and wheels as set W.
Step 2: From Statement I, no bikes are two wheelers, so B and T do not intersect. Symbolically, B ∩ T = empty set.
Step 3: From Statement II, all wheels are bikes, so W lies completely inside B. Symbolically, W ⊆ B.
Step 4: Since W ⊆ B and B has no common part with T, anything inside W also cannot be in T. That means W and T are also disjoint.
Step 5: Therefore, it is true that no two wheelers are wheels, so Conclusion I follows.
Step 6: For Conclusion II, "All wheels are two wheelers" would require W ⊆ T, but we just deduced that W and T are disjoint, so this cannot be true in any valid diagram.
Verification / Alternative check:
Draw one circle for bikes and place wheels completely inside it. Draw another separate circle for two wheelers with no overlap with bikes. You will see that no element can belong to both wheels and two wheelers, so Conclusion I holds. At the same time, it is impossible that all wheels are two wheelers, which invalidates Conclusion II.
Why Other Options Are Wrong:
Option B claims that only Conclusion II follows, which is false because we have shown Conclusion II contradicts the diagram. Option C claims both conclusions follow, but Conclusion II does not follow. Option D says neither conclusion follows, but Conclusion I clearly follows. Option E talks of an either or situation, which is also incorrect because only Conclusion I logically follows from the given statements.
Common Pitfalls:
A common mistake is to rely on real world knowledge, such as the fact that in reality bikes are two wheelers. The question explicitly instructs you to ignore real world facts and trust only the given statements. Another common error is to think that if all wheels are bikes and bikes are two wheelers in real life, then both conclusions might follow. The correct approach is purely logical and set based, not factual.
Final Answer:
The correct option is Only conclusion I follows, because "No two wheelers are wheels" must be true, while "All wheels are two wheelers" is logically impossible under the given statements.
Discussion & Comments