Two-fifths of 1000 players is (2/5)*1000 = <<(2/5)*1000=400>>400 players
Three eights of 1000 players is (3/8)*1000 = <<(3/8)*1000=375>>375 players
The total number of players 25 or older is 400+375 = <<400+375=775>>775
The number of players younger than 25 years is 1000-775 = <<1000-775=225>>225 players
#### 225