Answer:
170 students were attending
Step-by-step explanation:
use a system of equations:
[tex]\left \{ {{x+y=300} \atop {9x+6y=2190}} \right.[/tex]
let x be the adults and y be the students
[tex]\left \{ {{-9(x+y=300)} \atop {9x+6y=2190}} \right.[/tex] multiply the top equation by -9 and add the two systems together to cancel out x. you are then left with:
[tex]-3y=-510[/tex]
divide both sides by -3 to leave y alone:
[tex]\frac{-3y}{-3}=\frac{-510}{-3}[/tex]
that would leave you with:
y=170
