Answer: He will use 2 musical notes to represent that 4 people chose country music.
Explanation:
Given : Tommy is making a picture graph to show his friends favorite kind of music.
He plans to use one musical note to represent 2 people.
i.e. Number of musical note to represent 1 people =

i.e. Number of musical note to represent 4 people =

i.e. Number of musical note to represent 4 people = 2
Hence, he will use 2 musical notes to represent that 4 people chose country music.