There were some students in Think Classroom. When the school bell rang, $$25$$ girls went outside to play hopscotch. The number of girls in the classroom became $$\frac{2}{3}$$ of the number of boys. After that, $$15$$ boys went to play soccer at the field. There is now an equal number of boys and girls inside Think Classroom. How many students were there in Think Classroom at first? 
Overseas Competition->Knowledge Point->Calculation Modules