gistfile1.rb

    def koeff
      1.0 / (department.first_semester_seminars_num + department.second_semester_seminars_num + 5)
    end

    def set_rate_after
      if exam_test? && exam_practice? && exam_theory?
        self.rate_after = (exam_test*0.1 + exam_practice*0.2 + exam_theory*0.7) * 10
      end
    end

    def set_before_rate
      sum = 0
      first_sem_seminars.each do |sem|
        sum += sem.to_i * koeff
      end
      second_sem_seminars.each do |sem|
        sum += sem.to_i * koeff
      end
      sum += i_semester * 2 * koeff if i_semester?
      sum += ii_semester * 2 * koeff if ii_semester?
      sum += illness_history * koeff if illness_history?
      self.before_rate = (sum * 10).round
    end

    def set_common_rate
      self.common_rate = (before_rate * 0.4 + rate_after * 0.6).round if before_rate? && rate_after?
    end