Question:
Which of the following are sets? Justify your answer
The collection of all rich persons of Kolkata.
Solution:
As the collection of all rich persons of Kolkata may vary from person to person. Someone considers a person whose income is Rs 1 lakh per annum as a rich person, and someone considers a person whose income is Rs 1 crore per annum as a rich person. Here, the set is not well – defined.
∴, this is not a set