What we know
The amount start's off at $6
Each mile adds $3
When he arrived it was $24
Tips are not added in the equation
Solving
The best way to do this to be honest would be to add all of it together as this is a pretty quick and easy method you can use and it's easy to check.
6+3+3+3+3+3+3 = 24
Adding these many 3's gives us the answer of 24
Meaning that Mike traveled 6 miles from his home to the airport
Statement
Therefore Mike traveled 6 miles during his trip from his home to the airport.
