Answer :
Explanation
Let the unknown pack of books x. Therefore;
[tex]3.79x\leq15[/tex]Hence;
[tex]\begin{gathered} 3.79x\leq15 \\ x\leq\frac{15}{3.79} \\ x\le\:3.95778 \end{gathered}[/tex]Answer: Mr Valentino can buy approximately 3 packs

Explanation
Let the unknown pack of books x. Therefore;
[tex]3.79x\leq15[/tex]Hence;
[tex]\begin{gathered} 3.79x\leq15 \\ x\leq\frac{15}{3.79} \\ x\le\:3.95778 \end{gathered}[/tex]Answer: Mr Valentino can buy approximately 3 packs