A point (x,y) is randomly selected such that 0 <= x <= 3 and 0 <= y <= 8. What is the probability that x + y <= 4? Express your answer as a common fraction.
See the graph below....
the trapezoid represents x + y < 4 area = 7.5
total double shaded rectangle area = 24
7.5/ 24 = 15/48 = 5/16