Aservice station has both self-service and full-service islands. on each island, there is a single regular unleaded pump with two hoses. let x denote the number of hoses being used on the self-service island at a particular time, and let y denote the number of hoses on the full-service island in use at that time. the joint pmf of x and y appears in the accompanying tabulation. (give answers accurate to 3 decimal places.)