1. The float (or slack) of an activity is the amount of time that the activity can be delayed without delaying the overall project completion time. 2. Float is calculated as the difference between the latest start time and the earliest start time of the activity, or equivalently, the difference between the latest finish time and the earliest finish time. 3. Given the float is 3.5 days, this means the activity can be delayed by up to 3.5 days without affecting the minimum project completion time. 4. Float helps identify non-critical activities that have scheduling flexibility, unlike critical activities which have zero float and must be completed on time to avoid delaying the project. 5. In this context, a float of 3.5 days indicates that the activity is not on the critical path and has some leeway in scheduling.