You can
put this solution on YOUR website!When you say the ratio was 5:3 adults to kids, that means that out of 8 (5+3), 5 were adults and 3 were students.
You can then set up a ratio.
If 3 out of 8 are kids, then the total number of kids, X, to the total attendance is in a ratio.

There were 180 kids (and 300 adults) in attendance.