HEELLPPP PLZ I WILL MARK BRAINLEST

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

X^2/100+y^2/25=1 the length of the major axis is: a)5 b)10 c)20

What is the answer to question 11? will give extra points! include a explanation (reasonable) for you : )