Question

5) If A and B are finite set then (AB)​

Answer 1

AB is both finite and infinite set .

Answer 2

$if a \:and \: b \: are \: two \: finite \: sets \: such \: that \: acb \: then \: n(aub) = n(b)$

If A and B are two finite sets such that AcB , then (AUB)= n(B)