Keeping track of trip times

I imagine you're inserting two datas with the hour: once when you start your trip, and one when you finish it.

So let's say, travel 2 is from 02:40 PM to 3:20 PM and you have 2 columns (C and D) with this datas.

At first, you need to create a column E with the total time spent on the single trip (so it's D-C, in this case means 0:40).

Then if you use the SUM formula (or if you're using pivot table just add the total row at the end) and format the text as =TEXT(SUM(E2:E500);"[hh]:mm:ss") will show you the total amount of hours.

I attached what I thought. Obviously the yellow cells are at random, pls focus on the green ones.