A restaurant needs a staff of 3 waiters and 2 chefs to be properly staffed. The joint probability model for the number of waiter
s (X) and chefs (Y) that show up on any given day is given below. X Y 0 1 2 3 0 k 0.01 0.01 0.03 1 0.02 0.04 0.04 0.06 2 0.02 0.01 0.06 0.63 a) What must the value of k be for this to be a valid probability model