user: Question: How man teams had a total weight of 57.5?
Columns: ['Result', 'Date', 'Race', 'Venue', 'Group', 'Distance', 'Weight (kg)', 'Jockey', 'Winner/2nd']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Won', '21 August 1999', 'Warwick Stakes', 'Warwick Farm', 'G2', '1400 m', '55', 'L. Cassidy', '2nd - Tie The Knot']
SQL:

assistant: SELECT COUNT("Group") FROM "Table" WHERE "Weight (kg)" = '57.5';