Which Greek mathematician wrote the most definitive text on geometry, one that is still referred to today? A. Thales B. Pythagoras C. Euclid D. Archimedes E. Hippocrates Please help!!!

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