Six friends have an average height of 144 cm. A boy with a height of 150 cm leaves the group. Find the new average height.

Correct option is A

Given: Six friends have an average height of 144 cm. A boy with a height of 150 cm leaves the group.
Formula Used: New Average = ((Total sum of heights - Height of the boy who left))/((Number of friends - 1) )
Solution:
Total height of 6 friends = 6 × 144 = 864 cm.
New total height after the boy leaves = 864 - 150 = 714 cm.
Number of friends remaining = 6 - 1 = 5.
New average height = 714 / 5 = 142.8 cm.
Therefore, the new average height is 142.8 cm.