1.Let event Y be a rainstorm on a given day and event X be lightning on a given day. Let probability of these events be: P(X)=0.3 P(Y)=0.1 P(Y|X)=0.5 What is the probability that both rain and lightning occur on a given day?
2.A concentrated load of 200 kips is applied to the ground surface. What is the vertical stress increment due to the load at a point 15 ft below the ground surface at a horizontal distance of 10 ft from the line of the concentrated load?
3.A 12 ft x 12 ft square area carrying a uniform load of 5000 lb/ft^2 s applied to the ground surface.Find the vertical stress increment due to the load at a depth of 25 ft below the center of the loaded area.