<image> On a straight highway, there are three places A, B, and C, with place C located between places A and B. Car A is driving at a constant speed from place A towards place C, and Car B is driving at a constant speed from place B towards place A. During the driving processes of cars A and B, the functions representing the distances y (in kilometers) of each car from place C as a function of car A's driving time t (in hours) are shown in the figure. When car B arrives at place A, car A has already been resting at place C for ______ hours.