"IF" formula help needed for Numbers

Hi,



I need conditional formula help in Numbers. I am completely lost and would appreciate help here please. I am listening to PMI podcasts of different durations to earn PDUs. I am tracking the title and duration of each podcast. I need to enter the date I listened to each podcast, and add up all the durations I have listed to in one cell.



Column D is of type Duration (Hours and Minutes) of each podcast title, Column E is predominantly of type Date (that I listened to the podcast), except for the top cell which is of type Duration (Hours and Minutes). This top cell needs to hold the sum of the durations of all the podcasts I have listened to.



Basically what i want to achieve is this:



When I listen to a podcast, I shall enter the date in the appropriate cell in Column E. The moment I enter the date (meaning, if that cell is not blank), the top cell in that column should add the duration of that particular podcast to the existing value in that cell.



Is this even possible in Numbers? Have I described my issue clearly or have I made a mess of explaining?



Thanks and cheers

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