Given:
S={1, 2, 3, 4, 5, ........ 25}
A={3, 6, 9, 12, 15, 18, 21, 24}
B={4, 8, 12, 16, 20, 24}
To find:
[tex]A\cap B[/tex]The intersection denotes the common terms between the sets A and B.
So, the answer is,
[tex]A\cap B=\mleft\lbrace12,24\mright\rbrace[/tex]