Please answer if you are 100% sure for it. can be answered using any statistical tools. Also pls explain your answer

You receive on average 22 emails per day with a standard deviation of 4 emails. You know by experience that you can process 20 emails per hour with a standard deviation of 4 mails per hour. This evening you really only have 1 hour to clean up your inbox. . a Question: What is the chance you will process all your new mail this evening