Answer:
72 routes
Step-by-step explanation:
The total number of routes from city A to C by way of city B is determined as the product of picking one out 9 routes from A to B by picking one out of 8 routes from city B to C:
[tex]n= \frac{9!}{(9-1)!} *\frac{8!}{(8-1)!} =9*8\\n=72\ routes[/tex]
There are 72 different possible routes.