Finite Math
posted by Jennifer .
A manufacturing company in city A wishes to truck its product to 4 different cities, B, C, D, and E. If the cities are all interconnected by roads, how many different route plans can be constructed so that a single truck, starting from A, will visit each city exactly once, then return home?
Thank you for your help!!

3! = 3*2*1 = 12
Starting at A, he can go to B or C or D (three choices). From there, the driver has two choices. Then will have only one route left.
That sounds like an easy version of the standard traveling sales person problem.