How many 4-digit numbers can be created from the digits 6, 4, 2, 9, 7 and 1 without repeating any?

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