Which of the following collections are sets? Justify your answer:
(i) A collection of all natural numbers less than 50.
(ii) The collection of good hockey players in India.
(iii) The collection of all girls in your class.
(iv) The collection of most talented writers of India.
(v) The collection of difficult topics in mathematics.
(vi) The collection of all months of a year beginning with the letter J.
(Vii) A collection of novels written by Munshi Prem Chand.
(Viii) The collection of all question in this chapter.
(ix) A collection of most dangerous animals of the world.
(x) The collection of prime integers.
(i) The collection of all natural numbers less than 50 is a set because it is well defined.
(ii) The collection of good hockey players is not a set because the goodness of a hockey player is not defined here. So, it is not a set.
(iii) The collection of all girls in a class is a set, as it is well defined that all girls of the class are being talked about.
(iv) The collection of the most talented writers of India is a set because it is well defined.
(v) The collection of difficult topics in mathematics is not a set because a topic can be easy for one student while difficult for the other student.
(vi) The collection of all months of a year beginning with the letter J is a set given by {January, June, July}
(vii) A collection of novels written by Munshi Prem Chand is a set because one can determine whether the novel is written by Munshi Prem Chand or not.
(Viii) The collection of all question in this chapter is a set because one can easily check whether it is a question of the chapter or not.
(ix) A collection of most dangerous animals of the world is not a set because we cannot decide whether the animal is dangerous or not.
(x) The collection of prime integers is set given by {2, 3, 5........}