the mean weight of 60 students of a class is 40 kg the mean weight of boys is 50 kg while that of the girls is 30 kg find the number of boys and girls in the school ???
number of boys = b Total weight of boys, plus total weight of girls, equals total weight of all students 50b + 30(60-b) = 60*40=2400 50b + 1800 - 30b = 2400 20b = 600 b = 30 30 boys and 30 girls
