Question

Two finite sets A and B are said to be equivalent, if n(A)=n(B),
Equal sets are always equivalent, But, equivalent sets need not be equal.

Answer 1

Let $A=\{1,3,5\}andB=\{2,4,6\}$.
Then,n (A)=n(B)=3
So, A and B are equivalent.
Clearly, $A\ne B$.
Hence, A and B are equivalent sets but not equal.