Suppose that the demands for a company's product in weeks 1, 2, and 3 are each normally distributed. The means are 50, 45, and 60. The standard deviations are 10, 5, and 15. Assume that these three demands are probabilistically independent. a. Suppose that the company currently has 180 units in stock, and it will not be receiving any more shipments from its supplier for at least three weeks. What is the probability that stock will run out during this three-week period? Round your answer to three decimal places, if necessary. 0.909