Thanks Guru. I know I could add up all the individual durations of slides in sequence. What I actually do is take the start time of the first slide and the start time of the slide following the sequence, subtract them, to give me the duration. For this I need to use an on-line time calculator. For example, one sequence of 18 photos starts at 3:12.0 and ends at 4:22.0 which is 1:10.0.
I was hoping there was something to tell me what the duration was without having to calculate it.