i need help with this question

(a) A class has 26 students. 15 of the students have cats. 13 of the students have dogs. Find the different possible numbers of students who have both cats and dogs. i.e. The number of students who have both cats and dogs is between ______ and ________.

(b) A bakery sells 50 different types of donuts. 20 of the types of donuts contain chocolate. 12 of the types of donuts contain nuts. 5 of the types of donuts contain both chocolate and nuts. (i) How many of the types of donuts contain neither chocolate nor nuts? (ii) If a donut is chosen at random, what is the probability that it contains chocolate but not nuts?