Let $$\begin{array} { l }
U = \{ 1,2,3,4,5,6,7,8,9,10 \} \
A = \{ 2,3,4,5,6 \} \
B = \{ 4,5,6,7,8 \}
\end{array}$$ List all the members of the set. $A \cup B$
A) $\{ 2,3,4,5,6 \}$
B) $\{ 2,3,4,5,6,7,8 \}$
C) $\{ 4,5,6,7,8 \}$
D) $\{ 4,5,6 \}$
E) $\varnothing$

Question

Let $$\begin{array} { l } 
U = \{ 1,2,3,4,5,6,7,8,9,10 \} \
A = \{ 2,3,4,5,6 \} \
B = \{ 4,5,6,7,8 \}
\end{array}$$ List all the members of the set. $A \cup B$
A) $\{ 2,3,4,5,6 \}$
B) $\{ 2,3,4,5,6,7,8 \}$
C) $\{ 4,5,6,7,8 \}$
D) $\{ 4,5,6 \}$
E) $\varnothing$

Quizplus · Accepted Answer

The union of two sets includes all the elements that belong to at least one of the sets. Therefore, $A\cup B$ consists of all the elements in set $A$ and all the elements in set $B$. The common elements (4,5,6) are only counted once. This means $A\cup B$ equals $\{ 2,3,4,5,6,7,8 \}$.

Let U={1,2,3,4,5,6,7,8,9,10}A={2,3,4,5,6}B={4,5,6,7,8}\begin{array} { l } U = \{ 1,2,3,4,5,6,7,8,9,10 \} \\A = \{ 2,3,4,5,6 \} \\B = \{ 4,5,6,7,8 \}\end{array}U={1,2,3,4,5,6,7,8,9,10}A={2,3,4,5,6}B={4,5,6,7,8}​

Let $\begin{array} { l } U = \{ 1,2,3,4,5,6,7,8,9,10 \} \\A = \{ 2,3,4,5,6 \} \\B = \{ 4,5,6,7,8 \}\end{array}$