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.

Answer + explanation:

1. Writing the function

You know that for every mile it costs 40 cents, or 0.4 dollars, so you can write this as 0.4m.

You also know that there is an initial fare of 2.5, so you add that.

Then you have F = 0.4m + 2.5

2. Find the better choice

Since she has to travel 5 miles, you can plug m = 5 into the function to see the cost:

F = 0.4 * 5 + 2.5

F = 2 + 2.5

F = 4.5 or $4.50

Since $4.50 < $8.00, you know that the cab would be the cheaper and better option.

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step-by-step explanation: