diff --git a/projectnetwork.go b/projectnetwork.go
index e15e58d..13559ea 100644
--- a/projectnetwork.go
+++ b/projectnetwork.go
@@ -70,13 +70,7 @@ func (g *projectNetwork) forwardPass(toposort []*activity) {
 // backwardPass computes the late times and slack for each activity using the
 // early times
 func (g *projectNetwork) backwardPass(toposort []*activity) {
-	n := len(toposort)
-
-	end := toposort[n-1]
-	end.lateFinish = end.earlyFinish
-	end.lateStart = end.lateFinish - end.duration
-
-	for i := n - 2; i >= 0; i-- {
+	for i := len(toposort) - 1; i >= 0; i-- {
 		a := toposort[i]
 		g.setLateTimes(a)
 	}
@@ -102,6 +96,10 @@ func (g *projectNetwork) setLateTimes(a *activity) {
 		s := successors.Node().(*activity)
 		lf = math.Min(lf, s.lateStart)
 	}
+
+	if lf == math.Inf(1) {
+		lf = a.earlyFinish
+	}
 	a.lateFinish = lf
 	a.lateStart = a.lateFinish - a.duration
 	a.slack = a.lateFinish - a.earlyFinish