12. A bus travels between the two cities *A* and *B*, which are 100 miles apart. If the bus has a breakdown, the distance from the breakdown to city *A* has a uniform distribution over (0, 100). There is a bus service station in city *A*, in *B*, and in the center of the route between *A* and *B*. It is suggested that it would be more efficient to have the three stations located 25, 50, and 75 miles, respectively, from *A*. Do you agree? Why?