To determine how many adults you need for a gathering of Girl Scouts, you must use the requirements based on the lowest program level girl in attendance.  For example, if you have  Brownies and Juniors, you must use the ratio requirements for Brownies.

DAISY:

-- For troop meetings:
      -- You must have two unrelated adults (at least one of whom is female) for up to 12 Daisies plus one additional adult for every 6 more:
              -- 1 - 12 Daisies:  2 adults
              -- 13 - 18 Daisies:  3 adults
              -- 19 - 24 Daisies:  4 adults
              -- etc.
-- For all other events (e.g., field trips, camping):
      -- You must have two unrelated adults (at least one of whom is female) for up to 6 Daisies plus one additional adult for every 4 more:
              -- 1 - 6 Daisies:  2 adults
              -- 7 - 10 Daisies:  3 adults
              -- 11 - 14 Daisies:  4 adults
              -- etc.

BROWNIE:

-- For troop meetings:
      -- You must have two unrelated adults (at least one of whom is female) for up to 20 Brownies plus one additional adult for every 8 more:
              -- 1 - 20 Brownies:  2 adults
              -- 21 - 28 Brownies:  3 adults
              -- 29 - 36 Brownies:  4 adults
              -- etc.
-- For all other events (e.g., field trips, camping):
      -- You must have two unrelated adults (at least one of whom is female) for up to 12 Brownies plus one additional adult for every 6 more:
              -- 1 - 12 Brownies:  2 adults
              -- 13 - 18 Brownies:  3 adults
              -- 19 - 24 Brownies:  4 adults
              -- etc.

JUNIOR:

-- For troop meetings:
      -- You must have two unrelated adults (at least one of whom is female) for up to 25 Juniors plus one additional adult for every 10 more:
              -- 1 - 25 Juniors:  2 adults
              -- 26 - 35 Juniors:  3 adults
              -- 36 - 45 Juniors:  4 adults
              -- etc.
-- For all other events (e.g., field trips, camping):
      -- You must have two unrelated adults (at least one of whom is female) for up to 16 Juniors plus one additional adult for every 8 more:
              -- 1 - 16 Juniors:  2 adults
              -- 17 - 24 Juniors:  3 adults
              -- 25 - 32 Juniors:  4 adults
              -- etc.

CADETTE:

-- For troop meetings:
      -- You must have two unrelated adults (at least one of whom is female) for up to 25 Cadettes plus one additional adult for every 12 more:
              -- 1 - 25 Cadettes:  2 adults
              -- 26 - 37 Cadettes:  3 adults
              -- 38 - 49 Cadettes:  4 adults
              -- etc.
-- For all other events (e.g., field trips, camping):
      -- You must have two unrelated adults (at least one of whom is female) for up to 20 Cadettes plus one additional adult for every 10 more:
              -- 1 - 20 Cadettes:  2 adults
              -- 21 - 30 Cadettes:  3 adults
              -- 31 - 40 Cadettes:  4 adults
              -- etc.

SENIOR & AMBASSADOR:

-- For troop meetings:
      -- You must have two unrelated adults (at least one of whom is female) for up to 30 Seniors plus one additional adult for every 15 more:
              -- 1 - 30 Seniors:  2 adults
              -- 31 - 45 Seniors:  3 adults
              -- 46 - 60 Seniors:  4 adults
              -- etc.
-- For all other events (e.g., field trips, camping):
      -- You must have two unrelated adults (at least one of whom is female) for up to 24 Seniors plus one additional adult for every 12 more:
              -- 1 - 24 Seniors:  2 adults
              -- 25 - 36 Seniors:  3 adults
              -- 37 - 48 Seniors:  4 adults
              -- etc.