Let there are x total student surveyed, the 1/4x students prefer red, 1/8x prefer blue.
Determine the remaining students.
[tex]\begin{gathered} S=x-\frac{x}{4}-\frac{x}{8} \\ =\frac{8x-2x-x}{8} \\ =\frac{5}{8}x \end{gathered}[/tex]Determine the students that prefer green.
[tex]\frac{3}{5}\cdot\frac{5}{8}x=\frac{3x}{8}[/tex]The students who preferred green is 15. So equation for x is,
[tex]\begin{gathered} \frac{3x}{8}=15 \\ x=\frac{15\cdot8}{3} \\ =40 \end{gathered}[/tex]So total students that were surveyed is equal to 40.
