(b ) Twelve percent of the engines manufactured are defective. If engines are randomly selected, calculate the probability that (i) the first non-defective engine will be found on the fourth engine, (3 marks) (ii) the third non defective engine will be found on the sixth engine, (3 marks) (iii) at most fifteen engines are defective after tested 100 engines. (6 marks) (Total: 20 marks)