Five flats:
B-flat, E-flat, A-flat, D-flat, G-flat.
It means the key signature of the following music is in the key of F major of D minor
There are three flats in the key signature of E flat major
Safe and Sound is in the concert key of C (or no flats or sharps). On a B flat trumpet, that would be the key of D (or 2 sharps).
A flat lowers the note by a semitone. As a key signature, a single flat indicates the key of F, meaning your B should be flat. Two flats are E and B, meaning the key is therefore B flat. B, E and A flat indicate the key of E flat ... and so on.
F major and its relative harmonic minor, D minor, have only b flat.
The key signature that has B flat, A flat, E flat and D flat is Concert A flat Major.
D major has a key signature of F sharp and C sharp D minor has a key signature of B flat
The key signature for F major has one flat (B flat) , while the key signature for F minor has four flats (B flat, E flat, A flat, and D flat).
Assuming the key signature has only one flat (B Flat) then the key is either F Major, or D minor.
The key of D-flat has 5 flats: B, E, A, D and G.
That is the signature for the key of Db. Or, it's relative minor, Bb minor.
The key signature with only a B-flat is either F major or D minor.
The key signature with one flat is either F major or D minor.
B flat, E flat, A flat, D flat
B flat, E flat, A flat, D flat, G flat, C flat, F flat. It's the opposite order to that of the sharps in a key signature.
Only "B flat" is the key signature, then "C sharp" is the accidental.
B flat, E flat, A flat, D flat, G flat.