A taxi cab service charges an initial fare of $2.50 and then charges 40c per 1 mile traveled.
Write a function that can be used to determine the fare, F. in dollars, for the cab when m miles have been traveled.
Jillian needs to travel 5 miles. She can take the train, which costs $8.00 for a ticket, or she can take a cab. Determine the choice that would cost less and explain your reasoning.