Call the first school "School A." Call the rest of the schools "School B, School C, School D, and school E."
The ratio of boys to girls in school A is 1:2. Therefore:
Solving for x in that equation gives us 32 girls. Therefore, School A sent 48 kids in all.
School B - E have the same numbers. Therefore, the number of students sent to the conference is

. Therefore, 240 kids attended the conference.
Hope that helped!
~Cam943, Moderator