Midwest Publishing publishes textbooks. The company uses an 800 number where people can call to ask questions about the textbooks and place orders. Currently, there are 2 representatives handling inquiries. Calls occurring when both lines are in use get a busy signal. Each representative can handle 12 calls per hour. The arrival rate is 20 calls per hour. Required:
a. How many extension lines should be used if the company wants to handle 90% of the calls immediately?
b. What is the probability that a call will receive a busy signal if your recommendation in part (a) is used?
c. What percentage of calls receive a busy signal for the current telephone system with two extension lines?

A. 18 calls

B. 0.9

C. 20

Step-by-step explanation:

Number of representatives=2,

Number of extension lines=2,

Average calls each representative can accommodate per hour = 15 calls,

Arrival rate per hour = 30 calls

(a) 90% of the arrival rate = 0.09 × 20 = 18 calls

To handle 18 calls immediately, 18 extension lines should be used

(b) Probability is given by number of possible outcomes ÷ number of total outcomes

Number of possible outcomes = 18, number of total outcomes = 20

Probability (call will receive busy signal) = 18/20 = 0.9

(c) For one extension line, numbers of calls to receive busy signal = 20 - 10 = 10 calls

Number of calls to receive busy signal for the current telephone system with two extension lines = 2 × 10 = 20 calls

you are playing an adventure game on your computer. you come across a troll who won't let you pass and there is no other way to get to the other side of the river except over the bridge he is guarding.

the troll is a nerd. he takes great delight in watching people struggle with his problems. very few get them. he only gives you one chance and then he changes the puzzle. you have to solve this one.

before you are four blocks. they are numbered 11,6, -7,21.

he tells that the answer he wants is minus and between -1 and - 2. you can use +, -, ×, ÷   ( and ) as many times as you like or no times at all. you don't like the way he's looking at you, but you need to cross the bridge. what do you do?