In this paper. there were deduced three new lifetime distributions of serial-parallel and parallel-serial networks. their distribution being approached by means of analytical and Monte-Carlo methods. The novelty of the distribution consists in the fact that the number of subnets is random. https://www.nacrack.com/amazing-price-1997-2000-BMW-528I-Front-Bumper-Reinforcement-Bar-Used-Original-Exterior-OEM-great-save/