Loading....
Coupon Accepted Successfully!

 

Worked Examples: Type II (More Than Two Conclusions are Given)

In each of the questions given below, there are two statements followed by four conclusions, A, B, C and D. You have to take the two given statements to be true even if they seem to be at variance from the commonly known facts. Read all the conclusions and then decide which of the given conclusions logically follow from the two given statements, disregarding commonly known facts.
 

Example-1

St. I—All cats are dogs.

 

St. II—No dog is black.

 

Con A—No black thing is cat.

 

Con B—No cat is black.

 

Con C—Some black things are cats.

 

Con D—All dogs are cats.

  1. None follows
  2. Only D follows
  3. Only A follows
  4. Only A and B follow
  5. None of these

Solution

Since statement II is negative, the conclusion should also be negative (rule 7). Hence, conclusions C and D do not follow. Now in conclusion A, both the terms ‘black’ and ‘cats’ are distributed. These terms are also distributed in the statements. So conclusion A follows. Similarly, conclusion B also follows.

 

Hence, we can conclude that only conclusions A and B follow.

 

Answer: (4)

Analysis with Venn diagram.

 

Description: 110791.png

 

From the above diagram, we observe that no black thing is cat and no cat is black. Hence, only conclusions A and B follow.
 

 

Example-2

St. I—Some parrots are mangoes.

 

St. II—All mangoes are apples.

 

Con A—All apples are mangoes.

 

Con B—All parrots are apples.

 

Con C—Some parrots are apples.

 

Con D—Some mangoes are parrots.

  1. Only A and B follow
  2. All follow
  3. Only C and D follow
  4. Only B and C follow
  5. None follows

Solution

Since one of the premises is particular, the conclusion should be particular. Therefore, conclusions A and B do not follow. Conclusion C is particular and it is a mediate inference. Conclusion D is an immediate inference drawn from statement I. Both conclusions C and D follow.

 

Answer: (3)
 

Analysis with Venn diagram.

 

Description: 110803.png

 

From the diagram, we notice that some parrots are apples and some mangoes are parrots. Hence, both the conclusions C and D follow.
 

 

Example-3

St. I—All stars are planets.

 

St. II—All planets are clocks.

 

Con A—All planets are stars.

 

Con B—All stars are clocks.

 

Con C—All clocks are planets.

 

Con D—Some clocks are stars.

  1. Only C, B and D follow
  2. Only A and B follow
  3. None follows
  4. All follow
  5. Only B and D follow

Solution

Since both the premises are affirmative, the conclusion should be affirmative (rule 8).

Conclusion A is an immediate inference drawn from premise I. The term ‘planets’ is distributed in conclusion A without being distributed in premise I. So, conclusion A does not follow.

 

In conclusion B, the term ‘stars’ is distributed and this term is distributed in premise I also. So, conclusion B follows.

 

In conclusion C, the term ‘clocks’ is distributed without being distributed in any of the premises. So, conclusion C does not follow.

 

Conclusion D can be derived from conclusion B. So, conclusion D also follows.

 

Answer: (5)
 

Analysis with Venn diagram.

 

Description: 110816.png

 

From the diagram, we observe that only conclusions B and D follow.
 

 

Example-4

St. I—All typists are stenographers.

 

St. II—Some stenographers are girls.

 

Con A—All girls are stenographers.

 

Con B—All girls are typists.

 

Con C—Some typists are girls.

 

Con D—No typist is a girl.

  1. Only A follows
  2. Only B and C follow
  3. Only either B or C follows
  4. Only either C or D follows
  5. None follows

Solution

Since the middle term is not distributed even once in the premises, no conclusion follows (rule 2). Conclusions C and D contradict each other. Both of them cannot be false simultaneously. When conclusion C is true, conclusion D is definitely false. When conclusion D is true, conclusion C is definitely false. Hence, either conclusion C or conclusion D follows.

 

Answer: (4)

Analysis with Venn diagram.

 


 

From the diagram, we notice that either conclusion C or conclusion D follows.
 





Test Your Skills Now!
Take a Quiz now
Reviewer Name