chebyshev and markov

Let x be the number of transactions carried out in one day on the Mexican stock market, with an average of 15 and its dispersion index is 1.5, apply Chebyshev and Markov in any of its variants: A. Interpret and say how the magnitude that maximizes the probability should be b. What will be the required magnitude to be able to have a probability of .75 in these transactions c. What specific Distribution is being taken into account for this analysis of both inequalities