Hi,
 Im preparing for PMP and have a question on Estimate Activity Duration process. Why does PMBOK has a process called "Estimate Activity Duration" and does not have a process called "Estimate Activity Effort"? PMBOK suggest to use Activity Duration Estimate to calculate cost.  

  As an example if we consider an activity, painting a room, is going to take 8 hours of effort and if the resource is allocated 50% per day, the duration goes to two days. Where as we should pay for 8 hours of