First off, you need to find the two equations for this question. First equation is to find the equation for the number of students going for dance session. Next is to find the equation for the number of students going for the singing session. And that equation has 2 parts to it, one part is taking 1/4 from the people attending the dance session while the other part is to take the total number of students attending the camp minus the students attending the dance and basketball sessions.