Question

what problem did the dj need to fix?
problem
solutions
knowing when to play popular songs
getting the crowd to enjoy the music
key ideas
summary
djs want people to enjoy the music that they play. for this reason, they connect with the crowd by playing music that is personal to them. djs listen and watch the crowd so they can decide what music to play. in fact, they look for the right time to carefully move to a new song. in addition, djs take song requests or use popular songs to excite the crowd. a successful dj must listen, watch, and talk to the crowd while people dance and enjoy the music.

Explanation:

From the "Key Ideas" summary, the DJ's goal is to have the crowd enjoy the music. The "Problem" section would relate to what needs fixing, and the solution "getting the crowd to enjoy the music" implies the problem is about achieving that. So the problem the DJ needed to fix is getting the crowd to enjoy the music.

Answer:

getting the crowd to enjoy the music