How many melodies? #2
My toy piano keyboard has 7 distinct white notes: letters A-G in English alphabet. I'm going to create a melody by playing three random notes. I am not allowed to repeat any notes and the melody cannot be ended with E, F or G. How many different melodies can I play?
- C G A is permitted.
- A F A isn't permitted because of repetition.
- A B E is not permitted because of last note rule.