Please answer correctly else leave. also explain the result

You receive on average 20 emails per day with a standard deviation of 3 emails. You know by experience that you can process 18 emails per hour. Every evening you block a slot of 1 hour in your agenda to clean up your inbox. Question: What is the chance you will process all your new mail this evening? You also always read the tip of the day" on your computer and today's tip was on auto-deleting unwanted mail from your inbox. For you this would reduce the number of mails with 4 mails. Question: What is the chance now you will process all your new mail this evening