The PI rule using the headcount constraint alone selects IV, II, III, I, and V, because the project with the next highest PI (that is NPV/Headcount), V, cannot be undertaken without violating the resource constraint. These projects are also feasible to do under the current capital budget because they happen to require exactly $60 million in capital. The only other feasible possibility is to take only project V, which generates a lower NPV, so this choice of projects is optimal.