If the probability of playing a classical piece is two-fifths, that means that two-fifths of the songs on Jack's music player are classical.
Can you create and solve a proportion to find out how many songs out of 120 are classical.
Jack has 48 classical songs on his music player. Can you find the number of jazz rock songs on his music player?
After you use a proportion to find how many jazz pieces Jack has, subtract the sum of classical and jazz songs from the total of 120 to find the number of rock songs on his music player.