<image> A motor vehicle had 42L of fuel in the tank before departure. After driving for some hours, it refuels at a gas station. The remaining fuel Q(L) in the tank as a function of the driving time t(h) is shown in the figure. Based on the figure, answer the following questions:
(1) The motor vehicle refuels after ______h of driving;
(2) The function relationship between the remaining fuel Q and driving time t before refueling is ______;
(3) The amount of fuel added at the gas station is ______L;
(4) If the gas station is 230km away from the destination and the vehicle speed is 40km/h, is there enough fuel in the tank to reach the destination? Please explain your reasoning.