We investigate the rate of convergence of the direct-simulation estimator ˆ xp(n) of a large quantile xp of the Pareto and Gamma distributions. The upper bound of the probability P{|xp(n)- xp|>ε is determined. [Projekat Ministartsva nauke Republike Srbije, br. 174020: Geometry and Topology of Manifolds, Classical Mechanics and Integrable Dynamical Systems]