[tex]\displaystyle\\
a)\\
\sqrt{15} \ \textless \ \sqrt{16} = 4\\
\sqrt{225} = 15\\
\Longrightarrow~~ x \in \{4;~5;~6;~7;~8;~9;~10;~11;~12;~13;~14;~15\}\\
\Longrightarrow~~A=\{4;~5;~6;~7;~8;~9;~10;~11;~12;~13;~14;~15\}\\\\
b)\\
\text{Nr de elemente ale multimii } = 15 - 4 + 1 =11+1 = 12 \text{ elemente.}\\
\text{Cazuri favorabile: }~\{4;~9\}~~~2 \text{ elemente}\\
p = \frac{2}{12}= \frac{1}{6}[/tex]
