[tex]\begin{gathered} \text{The number of girls is 11.} \\ \text{The number of boys is 9.} \\ \text{The total number of students in the class is,} \\ T=11+9 \\ T=20 \\ Percentage\text{ of boys in the class is,} \\ \text{Percantage}=\frac{\text{Boys}}{\text{Total}}\times100 \\ \text{Percantage}=\frac{9}{20}\times100 \\ \text{percntage}=45 \end{gathered}[/tex]
Thus, the boys percantage is 45%.