Past exam of the Probability, statistics and options II course of the University of Oxford / 2011 / M / M4 / b / v

The event $T\ge 5$ is the same as $2^T\ge 32$. Apply Markov's inequality to the nonnegative random variable $2^T$ and use part (iv):The strict numerical comparison is enough even though the probabilistic inequality itself is non-strict.