Question

A sales representative can take one of 4 4 different routes from city upper c city c to city upper f city f and any one of 5 5 different routes from city upper f city f to city upper m city m. how many different routes can she take from city upper c city c to city upper m city m​, going through city upper f city f​?

Answer 1

She can take one of 20 routes.

The fundamental counting principle states that the total number of choices is equal to the product of the numbers of choices:

4 routes * 5 routes = 20 routes