PDF chapter test TRY NOW

If X = \{y : y = 5n, n \in \mathbb{N} and n \le 3\}Y = \{y : y = 5n, n \in \mathbb{N} and n \le 3\}, then find the following.
 
(i) Commutative property of intersection of sets:
 
(ii) Y \cap X =