Ib applications

[Maximum mark: 6) Students in a Physics class are about to take an oral exam. The teacher prepares a batch of questions for the exam which consists of 7 theoretical questions and 11 practical questions. Every question is written on a folded piece of paper. Each student selects one of these pieces of paper at random and answers the question on it. The piece of paper will be placed back to the batch after being answered. (a) Find the probability of a student selecting a theoretical question. There are 18 students in the class. Find the probability that (b) 6 students select a theoretical question: (c) no more than 12 students select a practical