Answer:
220
Step-by-step explanation:
This is a selection problem. We want to know the number of different sequences of 3 notes that are possible.
This can be solved using a combination approach. The question can be rephrased as in how many ways can 3 notes sequence be obtained from 12 notes in the vocal range
This is 12C3 = 12!/(12-3)!3! = 220
They are 220 possible different sequences
