The Tourist Delivery Program was developed by several European automakers. In this program, a tourist from outside Europe--most are from the United States-may purchase an automobile in Europe and drive it in Europe for as long as six months, after which the manufacturer will ship the car to the tourist's home destination at no
additional cost. In addition to the time limitations imposed, some countries impose mileage restrictions so that tourists will not misuse the privileges of the program. In setting the limitation, some countries use a normal distribution assumption. It is believed that the number of kilometers driven by a tourist in the program is normally distributed with mean 4,500 and standard deviation 1,800. If a country wants to set the mileage limit at a point such that 80% of the tourists in the program will want to drive fewer kilometers, what should the limit be?