The average weight of 24 students is 35 kg If weight of teacher is also included then average = 35.4 kg ( 35 kg + 400 gram) Concept: Total weight = Average weight × Number of persons Calculation: Total weight of 24 students = 24 × 35 = 840 kg Total weight of 24 students and 1 class teacher =25×35.4=885 kg ∴ Weight of class teacher =885−840=45 kg