Bag contains 5 red marbles and 3 black marbles, For atleast one of the three marbles drawn be black, if the first marble is red,then the following situations are possible Event E1 = Second marble is black and third is red Event E2 = Second marble is black and third is also black (E2)Event E3 = Second marble is red and third is black (E3)Let Event Ri = drawing red marble in ith draw Event Bi = drawing black marble in ith draw