How would one answer the question below? What distribution would you use?

3. Two combination drug therapies {Treatment A and Treatment B] hays been deyeloped for eradicating Helicobacter pyfoni in human patients. The effectiveness of these treatments depends on whether or not the patient is resistant to the chemical compound Metronidazole, but a patient's resistance status is not routinely determined before beginning treatment. Treatment A successfully eradicates Hefrcobacter pyfon' in 92% of resistant patients and BT34. of non-resistant patients. The corresponding proportions for Treatment B are ?5% and 95%. (i) Denote by B {D r: B s 1) the proportion of the affected population that is resistant. If a patient from this population is unsuccessfully treated with Treatment B, write down an expression for the probability that the patient is resistant. (ii) For what yalues of El would a greater proportion of patients from this population be successfully treated by Treatment B than by Treatment A? [iii] Suppose that B = 0.2. If 20 patients, selected at random from the affected population, are independently treated with Treatment B, nd the probability that at least 18 of them will be treated successfully. [4, 5, 5 MARKS]