dnhandley posted a question
Suppose that a product must go through an assembly line that consists of five sequential operations. The time it takes to complete each operation is normally distributed with a mean of 180 seconds and standard deviation of 5 seconds. Define the flow time to be the total time it takes a product to go through the assembly line from start to finish. What is the mean and standard deviation of the flow time? What is the probability that the total time will be less than 920 seconds?