How many hours has it been From June 3 2014 at 645am to June 5 2014 at 345pm?

From June 3, 2014, at 6:45 AM to June 5, 2014, at 3:45 PM is a span of 2 days and 9 hours. Specifically, from June 3 at 6:45 AM to June 5 at 6:45 AM is 48 hours, and then from 6:45 AM to 3:45 PM on June 5 is an additional 9 hours. Therefore, the total time is 48 hours + 9 hours = 57 hours.