Question: Six ships are docked in a harbor awaiting unloading. The times required to unload the ships are random variables with respective means of 0.6, 1.2, 2.5, 3.5, 0.4, and 1.8 hours. The ships are given a priority weighting based on tonnage. The respective tonnages are 12, 18, 9, 14, 4, and 10. In what sequence should the ships be unloaded in order to minimize the expected weighted time?