Problem P. 4448. (May 2012)
P. 4448. The speed of sound in carbon dioxide is 1.3 times as much as that of in air. Two children, sitting 2 and 2 metres from the opposite sides of a balloon which is filled with carbon dioxide, and hanged in the height of the heads of the children, found that the balloon ``reinforce'' their whisper the most, exactly at this position.
Estimate the diameter of the balloon.
Deadline expired on June 11, 2012.
Sorry, the solution is available only in Hungarian. Google translation
Megoldásvázlat. Az átmérő kb. 1,2 m.
30 students sent a solution. 5 points: Antalicz Balázs, Koncz Gabriella, Nagy Lajos, Papp Roland, Szabó 928 Attila. 4 points: Agócs Fruzsina, Demeter Dániel, Janzer Barnabás, Juhász Péter, Laczkó Zoltán Balázs, Szigeti Bertalan György. 3 points: 9 students. 2 points: 6 students. 1 point: 3 students. 0 point: 1 student.