Question

Relation from a set of even natural numbers to a set of prime numbers is such that elements from both sets are equal.
Number of elements in domain of the relation is

Answer 1

Set of even number : $\{2,4,\mathrm{6...}\}$
Set of prime natural number : $\{2,3,5,\mathrm{7...}\}$

Given: Relation is such that elements from both sets are equal.

We know that only 2 is even prime number.
Hence $R:\left\{\right(2,2\left)\right\}$