Question 3: Introduction to Normal Distribution. Suppose that at a country town petrol station, the daily demand for regular petrol is normally distributed with a mean of 1,000 litres and a standard deviation of 100 litres. The station manager has just opened the station for business and notes that there is exactly 1,100 litres of regular petrol in storage. The next delivery is scheduled later today at the close of business. The manager would like to know the probability that he will have enough regular petrol to satisfy today's demands. i.e. P(X