Question

A set A contains $3$ elements and set $B$ contains $4$ elements. The maximum number of elements in $AUB$ is

• A. 3
• B. 4
• C. 7
• D. 12

Answer 1

The correct option is C 7

The relation between the number of elements in two sets $A$ and $B$ with $AUB$ is given by, max$\left\{n\right(A),n(B\left)\right\}\le n\left(AUB\right)\le n\left(A\right)+n\left(B\right)$
Therefore, the maximum number of elements in $AUB$ is $3+4=7$