In a room, there are n persons whose average height is 160 cm. If m more persons, whose average height is 172 cm, enter the room, then the average height of all persons in the room becomes 164 cm. Then m : n is
Explanation:
Average height of n persons initially = 160 ∴ Sum of the heights of these n persons = 160n
Sum of the heighs of m persons joining = 172m
Total height of (n + m) persons = 160n + 172m
⇒ Average = 164 = 160n+172mn+m
⇒ 164n + 164m = 160n + 172m
⇒ 4n = 8m
⇒ m : n = 1 : 2
Hence, option (a).
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.