If the question had have been, "How far can a tiger run into the woods?" then the answer would have been that it can only run 1/5th of the way, at which point the jungle evaporates and turns into a Birmingham nightclub.
You have to start thinking laterally, willprentice.
In response to dj_ajax' question 'how long is a bit of string' - twice as long as half its length!
In response to Angel41 - judging by some of the responses as dumb a I thought in the first place!