The key signature will consist of two flats: Bb, and Eb.
Two flats, the same as Bb Major.
Bb has 2 Flats. Bb and Eb. The First Flat (Bb) Is on the second line from the bottom, and the second flat (Eb) is on the third space from the bottom.
The key signatures are the same in both clefts, but the flats are placed in different locations since the notes themselves are found in different places. The key of Eb major has three flats: Bb, Eb, and Ab.
Bb, Eb and Ab
The key with three flats (Bb, Eb, Ab) is the key of Eb.
The key signature will consist of two flats: Bb, and Eb.
Db Major, or Bb minor.
1, Bb.
Bb. B flat has two flats, the first two flats on the staff: Bb, and Eb. Also, the relative minor to Bb, G minor, also contains two flats in the key signature; Bb, and Eb. To find the relative minor to a major key, simply count down 2 and one half steps. ie: Bb, Ab, G, making the relative minor to Bb "G minor", which also has the same key signature.
Two flats, the same as Bb Major.
Bb C Db Eb F Gb A Bb Four notes have flats. The key signature would contain five flats for Bb minor, with accidentals used on the A naturals.
One, Bb. 1, the flat is B flat.
6 flats Bb, Eb, Ab, Db, Gb, Cb
One, Bb. 1, the flat is B flat.
It's not too bad, there's only three flats in the key signature; Bb, Eb, and Ab.
As pretty much anyone who plays a low brass instrument knows, there are two flats -- B flat and E flat ... in the key of B flat.