Scrum Ireland

So the Product Owner has listed the top priority items, the team has estimated how much they can do in a single Sprint, half way into a 3 week Sprint the Burndown Chart shows only 10developer days work out of estimated 30days work, what do you do now as a Team/Scrum Master? At the morning Scrum meeting the ScrumMaster points out that only 10 out of the 30 days are complete, this is what the Sprint Burndown Chart is for, to visualise the problems early on. If it ain't working then try something different. Get some tasks complete by tomorrow's Scrum needs to be the goal. Ask each team member what can be done to hurry along the completion of the items, something is holding up each developer, the developer must be honest and tell what the issue is could be; I haven't been focussed I'm being distracted by queries from outside the group I've had other tasks to do (This is a common one, but then why isn't the task listed in the Sprint backlog?). I don't understand ...