Develop a landing sequence that gives priority to those aircraft with the highest cost of slack time $($excess flying time multiplied by cost per minute of flying time$).$ For example, Flight $616$s $18\mathrm{.}75$ minutes of slack time $(223\mathrm{.}25)$ times $$300$ per minute means that if Flight $616$ does not land until its time is all used up$,$ it incurs an extra flying cost of $$5,625.$ Make a Gantt chart showing the landing sequence and evaluate the sequence in terms of performance. Calculate mean flow time, mean lateness, and aver$-$ age number of planes in the system.