A set of football matches is to be organized in a "round-robin"
fashion, i.e., every participating team plays a match against every other team
once and only once.
If 21 matches are totally played, how many teams participated?
Ò ans:7 teams okay.for a match u need 2 teams.suppose there r totally
'n 'teams.
Now uve to choose 2 teams out of 'n' teams.so answer =no of such
choices=no. of possible combinations. So we've ans =
nC2(ncombination2)=21;solve to get n=7.
Sol: n(n-1)/2=21. so n=7.if u don't understand c the graph below
each team plays no. of matches=no of teams ahead of it. One bar '|'
represents one team.
| | | | | | | ------------7
6 5 4 3 2 1 0 -----------21
last team is written as 0 matches becos this team has already played
with all other teams-hence sum of matches =6+5+4+3+2+1=21 which is
correct only if no of teams =7
Subscribe to:
Post Comments (Atom)
Posts
No comments:
Post a Comment