Three couples come together for a New Year's party. Shortly before midnight, they are counting the last seconds until it`s finally 12:00 a.m.. With a glass of champagne each, they toast the New Year.
How often do the glasses ring if everyone clinks glasses with each other in turn?
The glasses sound in total 15 times. This results from the following considerations:
Expressed in a formula, that means:
The sound of glasses = 0,5 * n * (n - 1)
n = Number of guests
The sound of glasses = 0,5 * 6 (6-1) = 15