The team's total number of goalies and defenders is 3+10 = <<3+10=13>>13.
The number of midfielders in the team is twice the number of defenders, which means there are 2*10=<<2*10=20>>20 defenders in the team.
The total number of players in the team playing the positions of goalies, defenders and midfielders is 20+13 = <<20+13=33>>33
If there are 40 players in the team, then the number of strikes in the team is 40-33 = <<40-33=7>>7
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