Question

The average weigh of a class of 40 boys is 55 kg. The average weight is raised to 56 kg. If the weight of teacher is added, then the weight of the teacher in kg. is

Answer 1

average = (sum of quantity)/ (no. of quantity)

here, 55 = (x1+x2+x3-----x40)/40

55*40 = (x1+x2+x3-----x40)

2200 = (x1+x2+x3----x40)

if the weight  of teacher is included, mean is equal = 56

56= {(x1+x2+3----x40)+weight of teacher}/41

56*41= 2200+weight of teacher

2296 = 2200 + wieght of teacher

2296- 2200 = wieght of teacher 

96kg = weight of teacher

Answer 2

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