TOPIC: Activity duration in a network diagram

Hi

I want to know if there is a difference where ES and EF is at the beginning of the week and LS is at the end of the week when doing duration of the activity. The question is activity in a network has the following characteristics: ES=12, EF = 22 and LS = 14. ES and LS relate to the beginning of the week whereas EF relates to the end of the week. what is the duration of this activity?

Thanks

Hi Carole and thanks for a good network diagram question.

The short answer to your question is that it the duration of any activity in a network diagram is equal to EF-ES. (Early Finish minus Early Start). In your particular question, the activity duration is 10 (EF-ES).
The long boring answer is; if the activity in question is on the critical path then its duration can also be calculated from LF-LS (Late Finish minus Late Start). This is because activities on the critical path have zero slack time. I hope that makes sense.