The mean weight of 25 students of a class is 52 kg. If the mean weight of the first 13 students of the class is 48 kg and that of the last 13 students is 55 kg. find the weight of the 13th student.

Given,


Mean weight of 25 students = 52 kg


Total weight of 25 students = 25 × 52 = 1300 kg


Mean weight of first 13 students = 48 kg


Total weight of First 13 students = 13 × 48 = 624 kg


Mean weight of last 13 students = 55 kg


Total weight of last 13 students = 13 × 55 = 715 kg


So,


Weight of 13th student = (sum of weight of first 13 and last 13 students) – (wt. of 25 students)


= (624 + 715) – 1300 = 1339 – 1300 = 39 kg


Hence, Weight of 13th student = 39 kg.


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