Not all tracks play in playlists on iPad

I have various playlists set up on my Windows 8.1 laptop. some of which I sync with my iPad.

I have noticed that although all the track names etc. appear in the Music app on the iPad, when I play the playlist, all the tracks do not play. I have two questions:

1) Is there a way to find out if the files are on the iPad but not playing, or if they're not actually there, and

2) a) If they are there, how do I get them to play, or

b) If they're not there, why not, and how do I get them there?

Thanks in advance, I hope that makes sense.