Can you hear this on the phone?

So lets say you were talking on your iphone to someone else on a phone call, and then all of a sudden your music starts to play on your phone and you hear it. Can the person on the other line hear it?

No. I was on the phone with my cousin and i started playing music on youtube or from an app. I asked "Can you hear the music?" It was quiet for a few seconds she replied with no.

No they won't be able to hear it at all

You might Ask the other person if it is audible…