Question

Average weight of class of 30 students is 40kg however if the weight of the teacher is included the average becomes 41kg whats the weight of teacher?

Answer 1

Answer:

71

Step-by-step explanation:

total weight of the students / no of students = average weight of students

total weight of students=40*30=1200kg

total weight of students including teacher= 41*31=1271kg

weight of teacher = weight of students including teacher-weight of students

=1271-1200=71kgs

Answer 2

Given is the average weight of a class of $30$ students, Find the weight of the teacher if the average weight including it is $41\ kg$.

Explanation:

• The average of data is the arithmetic mean of the data.
• It is mathematically calculated by dividing the sum of all data values by the total number of data values. $->\bar x=\frac{\sum x_i}{N}$
• Now for the average weight of the students we have, $N=30,\ \ \ \bar x=40$    
•              $->\bar x=\frac{\sum x_i}{N}\\ ->\sum x_i=40(30)\\->\sum x_i=1200$    
• Now when the teacher's weight denoted by 'W' is included we get, $N=31,\ \ \bar x'=41 \\->41=\frac{\sum x_i +W}{31} \\->\sum x_i +W=41(31)\\->W=1271-1200\\->W=71\ kg$    
• Hence, the weight of the teacher must be $71\ kg$.