A telephone exchange contains 10 lines. A line can be busy or available for calls and all lines act independently. If the probability that a line will be busy during the noon period is 0.8, what is the probability of there being at least three free lines during this period

What could explain what happened when the time was equal to 120 minutes

Graph y = -|x| + 2. click on the graph until the correct one appears.

Amachine that produces a special type of transistor (a component of computers) has a 2% defective rate. the production is considered a random process where each transistor is independent of the others. (a) what is the probability that the 10th transistor produced is the first with a defect? (b) what is the probability that the machine produces no defective transistors in a batch of 100? (c) on average, how many transistors would you expect to be produced before the first with a defect? what is the standard deviation? (d) another machine that also produces transistors has a 5% defective rate where each transistor is produced independent of the others. on average how many transistors would you expect to be produced with this machine before the first with a defect? what is the standard deviation? (e) based on your answers to parts (c) and (d), how does increasing the probability of an event a↵ect the mean and standard deviation of the wait time until success?