Question

The average weight of 35 students in a class is 35kg.if teacher is also included,the average increases by 1 kg.find the weight of the teacher

Answer 1

Concept:

Average weight = sum of weight of students/number of students

Given:

Total number of students = 35

Average weight of 35 students = 35 Kg

Find:

Weight of the teacher

Solution:

total weight of all the 35 students = 35×35 Kg

= 1225 Kg

Now, if a teacher is included, then

Total number of students and teacher = 35 students + 1 teacher = 36

after including the teacher, the average weight increases by 1 Kg,

So the average weight of students and teacher = 35Kg+1Kg = 36Kg

Total weight of students and teacher = 36×36Kg

= 1296 Kg

So, weight of teacher =  difference of total weight after adding the teacher and total weight before adding the teacher = 1296Kg - 1225Kg    

= 71 Kg

So the weight of the teacher is 71 Kg.

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