Let X ={ n ∈ N: 1 ≤ n ≤ 50}. If A ={ n ∈ X: n is a multiple of 2 } and B ={ n ∈ X: n is a multiple of 7 }, then the number of elements in the…

Let $\displaystyle \mathrm{X}=\{\mathrm{n} \in \mathrm{N}: 1 \leq \mathrm{n} \leq 50\}$. If $\displaystyle \mathrm{A}=\{\mathrm{n} \in \mathrm{X}: \mathrm{n}$ is a multiple of $\displaystyle 2 \}$ and $\displaystyle \mathrm{B}=\{\mathrm{n} \in \mathrm{X}: \mathrm{n}$ is a multiple of $\displaystyle 7 \}$, then the number of elements in the smallest subset of X containing both A and B is \_\_\_\_.