Question : Directions: Three statements are given followed by four conclusions numbered 1, 2, 3, and 4. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically does NOT follow(s) from the statements.
Statements:
Some Nights are Lights
No Light is a Van.
All Vans are Whips.
Conclusions:
1) Some Nights are not Vans.
2) No Van is a Light.
3) Some Whips are not Lights.
4) Some Nights are Whips.

Option 1: Only conclusion 4 does not follow

Option 2: Only conclusion 2 does not follow

Option 3: Only conclusion 1 does not follow

Option 4: Only conclusion 3 does not follow

Correct Answer: Only conclusion 4 does not follow

Solution : The possible Venn diagram according to the given statements is as follows –

Let's analyse the conclusions –
Conclusion (1): Some Nights are not Vans – From the Venn diagram, it is evident that some lights are nights and no lights are vans. So, from this, it can be concluded that some nights which are light are not vans. Thus, this conclusion follows.
Conclusion (2): No Van is a Light – From the Venn diagram, it is evident that there is a negative relation between vans and light. So, from this, it can be concluded that no van is a light. Thus, this conclusion follows.
Conclusion (3): Some Whips are not Lights – From the Venn diagram, it is evident that some whips are vans and no vans are light. So, it can be concluded that some whips which are vans are not light. Thus, this conclusion follows.
Conclusion (4): Some Nights are Whips – It is a possibility that the two circles representing nights and whips overlap and have a part of their area in common. But, this is not definite. So, this conclusion does not follow.

So, the only conclusion 4 does not follow. Hence, the first option is correct.