Answer
5.75 hours
This could also be written 5 hours 45 minutes.
Work Step by Step
If the flight leaves Miami at 10:00 AM Eastern Standard Time (EST), that means it leaves at 7:00 AM Pacific Standard TIme (PST). The flight arrives in San Francisco at 1:30 PST. (There is a 45 minute stop in Houston).
The total time from Miami to San Francisco is 6 hours and 30 minutes (6.5 hours). If we subtract the 45 minutes (0.75 hours) that the plane stops in Houston, we have a total in-air flight time of 5.75 hours (or 5 hours and 45 minutes).