Determination of Critical Path:

Now, our aim is to hit upon the critical path having the longest sequence of activities through the network that is referred as the path with zero slack time. In the underlying case, there are two critical paths that are P-Q-S and P-R-S with duration of 4 days and 3 days. By definition of critical path, P-Q-S is the critical path. The property of critical path is that if any activity is delayed then the overall project is delayed.