Flight time from Houston to Orlando is 2 hours to 20 minutes. I arrived at Orlando at 4:15 pm. What time did I set of ?

1:55 pm

Step-by-step explanation:

So, you arrive at 4: 15 pm in Orlando after a 2 hr and 20 minute flight from Houston.  So, lets start with the easy part: let's subtract the 2 hrs part.  

2 hrs earlier from 4:15 pm is 2:15 pm.

Then, you have to subtract the 20 minutes.  Well, it's quite obvious that if you left at 2:00 pm, that would be a total of 2 hrs and 15 minutes.  Just subtract the 15 minutes from the 2:15 pm.  However, it's 20 minutes, not 15, so you have to still subtract that last five minutes.  

So, 2:00 pm minus 5 minutes would equal 1:55 pm.