Question

average height of 27 students of a class is 160 cm. two student of 155cm and 165 join the class

Answer 1

Average of the height of 27 students = 160 cm (Given)

Sum of the height of 27 students = 160 x 27 = 4320 cm

.

Two students joined in:

Number of students = 27 + 2 = 29

Sum of their height = 4320 + 155 + 165 = 4640 cm

.

Find the average of the 29 students:

4640 ÷ 29 = 160 cm

.

Answer: The average of the 29 students is still 160 cm

Answer 2

The height of average 27 student =160
2 student join 27+2=29
The new 2 student average height =165-155=10
Then average height of 29 student =
$\frac{29x160}{29 } = 160$
So the the average of 29 student is also 160