Question

pls it is very important tell me the answer ​

Answer 1

Answer:

Only 2 and 3 .

Step-by-step explanation:

The well defined sets are :- Set of even Numbers less than 20.

:- The set of even Numbers greater than 10.

We consider them as well defined sets as they contain elements that is fixed and cannot be changed by anyone. It's a general truth. On the other hand the other sets depends on the thinking capability of the person and changes with respect to the situation.

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