19. Suppose that, in a temperate coniferous forest, 60% of randomly selected quarter-acre plots have cedar trees, 45% have cypress trees, 30% have redwoods, 40% have both cedar and cypress, 25% have cedar and redwoods, 20% have cypress and redwoods, and 80% of such plots have at least one of these trees. What is the probability that in a randomly selected quarter-acre plot in this forest we can find all three types of these trees?