I am completely lost on how to proceed with the below question. I need help in determining value of c and computing P(B1).

7. Let the sample space of an experiment be S = {0, 1, 2, . . . }, that is, a (countably) innite sample space. We dene events as follows: A0 = {0}, A1 = {1}, A2 = {2}, etc., B0 = {0,1,2,...}, B1 = {1, 2, 3, . . .}, B2 = {2,3,4, . . .}, etc. Formally, this means that A}, = {k} and Bk 2 {5 E S: s 2 k} for k E S. Suppose that P(Ak) : c4k/k! for k E S, so for instance P({0}) : 040/0! : c, etc. (Recall that O! = 1.) Determine the value of 0. Compute P(B1)