Collecting different answers to a simple problem

Collecting different answers to a simple problem

I am collecting different answers to the problem below for possible
publication in a pedagogical note I am writing. Please post freely (avoid
repetitions). If I pick your answer I will contact you for permission
before using your contribution.
While driving on a looong straight highway with no other traffic, your GPS
displays your current speed $V+\varepsilon$, where $V$ is the official
speed limit in MPH. There is also an estimated time of arrival (ETA) to
your destination, and we assume this is just what it should be (a real GPS
usually adds corrections for traffic, stoplights, etc.)
Find a formula for the time needed to reduce the ETA by one minute in
terms of $V$ and $\varepsilon$.