the upper bound must be 1/3 if the desired time is 3 hours. The proof for Marcovs inequality can be found here: http://en.wikipedia.org/wiki/Markov%27s_inequality
the upper bound must be 1/3 if the desired time is 3 hours. The proof for Marcovs inequality can be found here: http://en.wikipedia.org/wiki/Markov%27s_inequality