A singer-songwriter wishes to compose a melody. Each note in the melody must be one of the 12 notes in her vocal range. How many different sequences of 3 notes are possible?

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