Suppose the caravan travels 400 km, beginning in front of one tollbooth, passing through an intermediate tollbooth, and finishing just before the third tollbooth. Consider the following assumptions:

 Assumptions: 

• Ten cars in the caravan 

• A tollbooth services a car at a rate of one car every 9 seconds 

• A propagation speed of 100 km/hour 

• The distance between any of two adjacent toll booths is 200 km. 

• Whenever the first car of the caravan arrives at a tollbooth, it waits at the entrance until all the other cars have arrived and lined up behind it. 

How long does it take until the caravan is lined up before the third toll booth (from the first tool booth like the caravan analogy slide)?