Question

Mean weight of m boys is 43 kg. If the teacher who weighs 63kg is included the meanbecomes 45 kg.What is the value of m?

Answer 1

Answer :

Given,

Mean weight of m boys is 43kg.

When a teacher who weighs 63 kg is included the mean (average ) becomes 45 kg.

To find,

The value of m

Main solution :-

Let total mass of m boys be x.

Average of m boys = Total mass of m boys / no. of boys

43 = x/m (i)

Now,

New average = x+63/m+1.

45=x+63/m+1(ii)

We have two equations s and two unknown variables x and m.

43=x/m

x=43m

Putting this value of x in equation (ii)

45=43m+63/m+1

Performing cross multiplication:-

45m+45=43m+63

45m-43m=63-45

2m=18

m=9. ( Answer )

Answer 2

$\huge\bold\color{red}{Hello Mate}$

GIVEN :

Mean weight of m is 43kg

If the teacher who weighs 63kg is included the mean becomes 45kg

$\huge\bold{To Find}$

The value of "m"

Solution =>
Let total mass of m box is m.

Average of m boys = total number of boys

$43 = \frac{x}{m} - - - - - - - (1)$
Now,

Average =
$\frac{x + 63}{m + 1}$
$= > 45 = \frac{x + 63}{m + 1} - - - - - - - (2)$

=> 43=x/m
=> x=43m

Putting this in eqn 2

$45 = 43m + \frac{63}{m} + 1$
45m+45=43m + 63
45-43=63m-45m
2=18m
M=9
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