latest finish time of the activity. Thus, LS LF t L t ij ij ij j ij Step : Proceed backward to the next node i ( i < j ) in the sequence and compute the latest occurrence time at node i using min min L LS L t j ij j j ij , . Step : If j = (initial node), then min min L LS L t ij ij Critical path: The longest path connected by the activities in the network is called the critical path. A path along which it takes the longest duration.
For the activity (i,j), to lie on the critical path, following conditions must be satisfied: (i) E L and E L j j (ii) E E L L t j j ij Example . Compute the earliest start time, earliest finish time ,latest start time and latest finish time of each activity of the project given below: - - Activity - - - - - - Duration ( in days) Earliest start time (EST) and latest finish time (LFT) of each activity are given ithe following network. Fig . E = L = E = L = E = L = E = L = E = L = E = L = E = E + t = + = L = L – t = – = E = E + t = + = L = L – t = – = E = E + t or E + t L = L – t or L – t = + = = – = (take E + t or E + t (take L – t or L – t whichever is maximum) whichever is minimum) E