In chess tournament where the participants were to play one game with another, two players fell ill having played 3 games each. If the total number of games played is 84,the number of participants at the beginning was

Let n be the no of participants excluding the two particular persons who felt ill ⇒nc2=84−(3+3) ⇒nc2=78⇒n=13 Total no of participants =13+2 =15 Then the  number of participants at the beginning was 15