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.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 142.8 cm
The average height of the six friends = 144 cm
Therefore, the total height = Average Height × Number of Friends
⇒ the total height = 144 cm × 6 = 864 cm
The height of the boy who leaves is 150 cm.
Thus, the total height of the remaining friends will be:
⇒ New Total Height = Total Height − Height of Boy Leaving
⇒ New Total Height = 864 cm − 150 cm = 714 cm
New Average Height = Number of Remaining Friends/New Total Height
⇒ 714/5 cm = 142.8 cm