1. Choose A. Think of this problem this way: people see 12 cars from the time of departure to the time of arrival, and there are four cars on the road (including those just leaving and arriving), so the time from departure to arrival is actually the time when the fourth car arrives at 12 cars, and the middle distance is 8 time periods, 8*5=40 minutes.

2. choose c, assuming that the escalator has n floors. When A arrives, the escalator takes step n-36, and when B arrives, the escalator takes step n-24. Because the speed of the escalator is the same, then n-36 and n-24 are the time they spend. The speed of A is twice that of B, so 36/(n-36)=2*24/(n-24), and n=72, it is a 72-step escalator.