Hello,
If Bianca scored 48 of the 57 points, then 57-48 = 9 points were scored by the rest of her team.
If each teammate scored 3 points each, and the total number of points of the teammates is 9 points, then Bianca has 9/3 = 3 teammates.
However, the question asks how many players were on her team, so that includes Bianca, so the answer is 4 players.
Hope this helps!!