- DOI'I'BCU use or appropriate mathematical techniques 0 Accuracy and validity of any calculations or algebraic manipulations 0 Clear justication or explanation of techniques and rules used 0 Please show proper working out. Marks will be deducting for not showing step by step working out. 1. The American Automobile Association reports that the average time it takes to re pond to an emergency call is 25 minutes. Assume that the variable is normally distributed and the standard deviation is 4 minutes. If 80 calls are randomly se lected7 approximately how many will be responded to in a less than 15 minutes? (4 marks) 2. Let X be a normally distributed random variable with a mean of 6 and variance of 4. Let Z be a random variable with the standard normal distribution (a) Find P(X > 6). (2 marks) (b) Find 6 such that P(X > 7) : P(Z