Question: Suppose there are three roads from city A to city B and five roads from city B to city C.
a. How many ways is it possible to travel from city A to city C via city B?
b. How many different round-trip routes are there from city A to B to C to B and back to A?
c. How many different routes are there from city A to B to C to B and back to A in which no road is traversed twice?