The train is traveling at ~50mi/hr (73ft/s) when it passes a train robber.  The robber accelerates at 8ft/s² until reaching 90ft/s and then keeps that velocity in an attempt to reach the front of the train.  If the train is 4delta delta.delatdelta ft long and the robber reaches the front of the train 1 mile past the robber's starting point, what is a) the distance s the back of the train is past the robber before the robber starts moving, or b) the distance s before the back of the train reaches the robber.