The context of the following conversation is Robin was watching TV with the volume on very loud, so Kai asked Robin to turn it down.:
Robin says I'm sorry I bother Kai yesterday, I was watching tv so loud.
The friend responds You should just keep it at a decent level because otherwise he cant hear the teacher.
Robin responds I will keep it below 10 then..
The friend responds that sounds like a good deal, Kai will be happy..