An ambulance travels back and forth, at a constant specific speed v, along a road of length l. We may model the location X of the ambulance at any moment in time to be uniformly distributed over the interval (0,1). Also at any moment in time, an accident (not involving the ambulance itself) occurs at a point uniformly distributed on the road; that is, the location Y of the accident is also uniformly distributed over the interval (0,1). Assume the location of the accident and the location of the ambulance are independent. Supposing the ambulance is capable of immediate U-