Question

В шахматном турнире принимали участие 10 человек.Каждый участник сыграл со всеми остальными шахматистами по одной партий.Сколько было сыграно партий.

Answer 1

1 - девять партий, 2 - девять и т.п.
Выходит: 9*10=90 (партий)
и 90:2=45

Answer 2

Calculating the Number of Games Played in the Chess Tournament

To calculate the number of games played in the chess tournament where 10 participants played against each other, we can use the formula for combinations. The formula for combinations is given by:

nCr = n! / (r! * (n-r)!)

Where: - n = total number of participants - r = number of participants in each game (in this case, 2 for a game of chess)

Using this formula, we can calculate the number of games played.

Calculation

Using the formula nCr, where n = 10 and r = 2:

10C2 = 10! / (2! * (10-2)!)

10C2 = 10! / (2! * 8!)

10C2 = (10 * 9) / (2 * 1)

10C2 = 45

So, there were 45 games played in the chess tournament.