Question

Three sets $A,B\&C$ such that $A\subset B,$ then $A\cup (B\cup C)=$

• A. $B\cup C$
• B. $A\cup C$
• C. $B$

Answer 1

The correct option is A $B\cup C$

Given: Three sets $A,B\&C$ and $A\subset B$
$\Rightarrow A\cup B=B$

Using associative law:
$A\cup (B\cup C)=(A\cup B)\cup C$
$\Rightarrow A\cup (B\cup C)=B\cup C$