Question

Mean height of 11 friends is 154cm. If one friend of height Is left , find the new mean height.

Answer 1

Answer:

153.8 cm

Step-by-step explanation:

Formula :

Mean = sum of all observations / number of observations

Mean height of 11 friends = 154 cm

Mean = sum of all heights / 11

⇒ sum of heights = 11 × height

⇒ sum of heights = 11 × 154 cm

⇒ sum of heights = 1694 cm

One friend left .

Let his height be x .

One student left.

So 10 students are there

So mean becomes = sum / 10

⇒ mean = ( 1694 - x ) / 10

Here x is the height of the friend who left!

You told that x = 156 cm

So put this in the equation :

⇒ mean = ( 1694 cm - 156 cm ) / 10

⇒ mean = 1538 cm / 10

⇒ mean = 153.8 cm

Answer 2

Hello Friend

Here is your answer

As we know the formula

Mean = Sum of all the Observations/ Total Number of Observations

Total number of friends= 11

Mean of 11 friends = 154 cm

Hence

Sum of 11 Friends = Mean × Total Number
$= 154 \times 11 \\ = 1694$
Now
One friend is left whose height is 156 cm

Sum of Height of 10 friends = 1694 - 156
= 1538

Total friend is 10

Mean of 10 friends is
$= \frac{1538}{10} \\ \\ = 153.8 \: cm$
Therefore Mean of 10 friends is 153.8 cm

Hope it helps you