Suppose, you are running an experiment that has two outcomes, namely 'success' and 'failure'. You intially don't know the probability of success in a single experiment. But you know that, if you continue to run the experiment several times, the variance of the number of experiments required for the first success is 20. What is the expected number of experiments required for the first success ? [Hint: Try to determine the probability of success in a single experiment and recall the range of the values to which a probability must belong]