Math, asked by kaur97, 10 months ago

the mean weight of 35 students in a class is 45kg . If the weight of class teacher is also included , the mean weight increase by 0.5 kg . Find the weight of class teacher​

Answers

Answered by Anonymous
25

Given :

  • The mean weight of 35 students in a class is 45kg.
  • If the weight of class teacher is also included the mean weight increase by 0.5 kg.

To Find :

  • Weight of class teacher.

Solution :

We have mean weight of 35 students as 45 kg.

We know the formula for mean.

Formula :

\large{\boxed{\sf{\red{Mean\:=\:\dfrac{Sum\:of\:observations}{Total\:number\:of\:observations}}}}}

Mean = 45

Total number of observation 35

Sum of observation = x

Block in the data in the formula,

\longrightarrow \sf{45\:=\:\dfrac{x}{35}}

\longrightarrow \sf{1575\:=\:x}

\large{\boxed{\rm{\blue{Sum\:of\:observation\:=\:x\:=\:1575}}}}

Now, weight of a teacher is included in the mean. The mean weight increases by 0.5

° New mean weight = 45 + 0.5 = 45.5 kg.

The weight of 35 student was 45 kg. Since, the weight of teacher is added, the total number of observation which was 35 will now become 36.

Block in the data in the formula of mean,

\longrightarrow \sf{45.5\:=\:\dfrac{Sum\:of\:observations}{36}}

\longrightarrow \sf{45.5\:\times\:36\:=\:Sum\:of\:observation}

\longrightarrow \sf{1638\:=\:Sum\:of\:observation}

\large{\boxed{\sf{\pink{Sum\:of\:observation\:along\:with\:teacher's\:weight\:=\:1638}}}}

The weight of the class teacher will be the difference between the sum of observation of weight of 35 students (1575) and the sum of the observation of weight of 35 students along with the teacher's weight (1638)

Class teacher's weight :

\longrightarrow \sf{1638-1575}

\longrightarrow \sf{63}

\large{\boxed{\sf{\green{Weight\:of\:class\:teaher\:=\:63\:kg}}}}

Answered by Rythm14
36

Given :-

  • Mean weight of 35 students is 45kg.
  • If weight of teacher is included, mean weight increases by 0.5kg.

To find :-

  • Weight of teacher.

Solution :-

mean =  \frac{sum \: of \: observations}{total \: no. \: of \:observations }

Case 1

  • Mean weight of 35 students is 45kg

45 =  \frac{35}{total \: weight \: of \: 35 \: students}  \\  = >  total \: weight \: of \: 35 \: students \:  = 45 \times 35 \\  =  > 1575

Case 2

  • when teacher's weight is added, mean weight increases by 0.5
  • New mean weight is 45 + 0.5 = 45.5
  • total no. of people also increases by 36

45.5 =  \frac{36}{total \: weight \: of \: 36 \: people}  \\  =  > total \: weight \: of \: 36 \:  \: people \:  = 45.5 \times 36 = 1638

_________________________

Weight of class teacher,

Total weight of 36 people - Total weight of 35 students

= 1638 - 1575

= 63kg

________________________

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