Given:
In total there are 408 students who are enrolled in an introductory geology course.
Ratio of the number of boys to girls is 8:9
To find: Number of boys in the course.
Explanation:
[tex]\text{Let 8x and 9x be the number of boys and girls.}[/tex][tex]\begin{gathered} 8x+9x=408 \\ 17x=408 \\ x=\frac{408}{17} \\ x=24 \end{gathered}[/tex][tex]\begin{gathered} \text{Number of boys in the course=8}\times24 \\ =192 \end{gathered}[/tex]Therefore, number of boys in the course is 192.