Question

The average weight of a class of 39 students is 40 kg. if one of the students leaves the class then the mean is decreased by 200 g. find the weight of the student who left.

Answer 1

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Answer 2

Weight of student who left is 47.6 kg

1) Number of students in the class = 39

Average of weight of class = 40 kg.

Sum, of weight of complete class = 39*40 = 1560 Kg

2) One student leaves,

Number of remaining students = 39-1 = 38

Decrease in Average weight = 200g

new average weight = 39.8 kg

Sum of weight of complete class = 39.8 *38 = 1512.4 kg

3) Weight of student who left = 1560-1512.4 = 47.6 kg