I like to reduce everything by half if I don't already know the answer.

It just so happens that is the reduced fraction.
All I did was halve 18, which is 9, and halve 34, which is 17.
Each interior angle of a regular hexagon is 120°.
.. 4x +24° = 120°
.. 4x = 96° . . . . . . . subtract 24°
.. x = 24° . . . . . . . . divide by 4
216 ft per minute or 3.6 ft per second
515 divided by 216 is 2.38
it takes 2.38 minutes for the specified ant to crawl 515 feet