A job commences on Wednesday, January 3rd, and is scheduled to be completed on January 19th of the same year. How many days of float are there if the job was completed on January 15th?

To determine the amount of float in this project, we first need to understand the timeline of the job.

The job starts on January 3rd and is scheduled to finish on January 19th. This gives us a total duration of 17 days (from January 3 to January 19, inclusive).

If the job is completed early on January 15th, we need to calculate how many days earlier this completion is compared to the original schedule. The difference between the scheduled completion date of January 19th and the actual completion date of January 15th is 4 days.

Float, often referred to as "slack," is the amount of time that a project can be delayed without affecting its subsequent schedule. Here, since the job finished 4 days before the scheduled completion date, this indicates that there are 4 days of float available.

Therefore, the correct answer is that there are 4 days of float, as the project was completed earlier than planned, allowing for additional time within the original schedule without impacting the overall completion date.