Customers arrive at a checkout counter in a department store according to a Poisson distribution at an average of nine per hour. If it takes approximately ten minutes to serve each customer, find the mean and variance of the total service time in minutes for customers arriving during a 1-hour period. (Assume that a sufficient number of servers are available so that no customer must wait for service.)\

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

In which direction does the left side of the graph of this function point? f(x) = 3x3 - x2 + 4x - 2

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