Is the following relation a function? [(-2, 4). (-1.4), (0, 4), (1, 3), (5.5))​

At a pizza shop 70% of the customers order a pizza 25% of the customers order a salad and 15% of the customers order both a pizza and a salad if s customer is chosen at random what is the probability that he or she orders either a pizza or a salad