tournament with 8 teams. Each team play with others one match each. Minimum match a team should win to qualify in top 4. Approach?

Total number of matches in the round = 8C2 = 28

28/8 = 3.5

Assuming that there is no tie, all the teams cannot win the same number of matches.

So, if 4 teams win 4 matches each and the other 4 teams win 3 matches each, the first four teams are guaranteed to qualify. So, minimum number of matches to be won = 4