The problem is the following: The total time of a task must be calculated; given a day with time (for the beginning) and a time allotted for the task. Eg it starts on October 15, 2018 at 2:00 p.m., a task that will last 33.5hrs. It should be calculated when it ends assuming that lunches, meals and breaks do not count as part of working hours and each day has different non-working intervals.
The best example is the tasks assigned in the project manager where they adjust each day with the non-working intervals and the start date and assigned time are set and the automatic termination date is given