Originally Posted by: gmixstudiosi am working on music theory for dummies and i have tried to answer one of the questions but cant, what is a interval of 9 semi tones?[/quote]
A semitone is another term for half step. In other words a semitone equals a distance of 1 fret on a guitar.

9 semitones equals 9 frets. From the open E string to the 9th fret is an example:

E to F (1 half step)
F to F# (1 half step)
F# to G (1 half step)
G to G# (1 half step)
G# to A (1 half step)
A to A# (1 half step)
A# to B (1 half step)
B to C (1 half step)
C to C# (1 half step)

From E to C# is 9 half steps, or semitones. Or 5 and one half steps (5 whole steps and one additional half step). Or a major 6th. :)
[QUOTE=gmixstudios]so from a G flat to a D sharp

Is also 9 half steps.

Gb to G (1 half step)
G to Ab (1 half step)
Ab to A (1 half step)
A to Bb (1 half step)
Bb to B (1 half step)
B to C (1 half step)
C to Db (1 half step)
Db to D (1 half step)
D to D# (1 half step)

Make sense?