What is the travel time: depart 9: 30 am mst arrive 1: 30 pm pst ?

3 hours; how I solved it is by converting both time zones into Coordinated Universal Time (UTC). MST is 7 hours behind the UTC, and PST is 8 hours behind (you can find this on the internet).

To convert 9:30 to UTC, subtract 7 hours:

So, in UTC, the departure time was 2:30 AM

To convert 1:30 to UTC, subtract 8 hours (note that the time is 1:30 PM and not AM; so the time should be 13:30-- going by the 24 hour system):

So, in UTC, the arrival time was 5:30 AM

To find the total time traveled, you must subtract the arrival time by the departure time:
;;
so the travel time would be 3 hrs

Hope this helped :)