You are a representative for a cell phone company and it is your job to promote different cell phone plans.

a. your boss asks you to visually display three plans and compare them so you can point out the advantages of each plan to your customers.

•plan a costs a basic fee of $29.95 per month and 10 cents per text message.
• plan b costs a basic fee of $90.20 per month and has unlimited text messages.
•plan c costs a basic fee of $ 49.95 per month and 5 cents per text message.
•all plans offer unlimited calling.
•calling on nights and weekends are free.
• long distance calls are included.

b. a customer wants to know how to decide which plan will save her the most money. determine which plan has the lowest cost given the number of text messages a customer is likely to send.

Write an expression that has three terms and simplifies to 4x - 7. identify the coefficient(s) and constant(s) in your expression

Which of the following circles have their centers on the x-axis? check all that apply.

Aprisoner is trapped in a cell containing three doors. the first door leads to a tunnel that returns him to his cell after two days of travel. the second leads to a tunnel that returns him to his cell after three days of travel. the third door leads immediately to freedom. (a) assuming that the prisoner will always select doors 1, 2 and 3 with probabili- ties 0.5,0.3,0.2 (respectively), what is the expected number of days until he reaches freedom? (b) assuming that the prisoner is always equally likely to choose among those doors that he has not used, what is the expected number of days until he reaches freedom? (in this version, if the prisoner initially tries door 1, for example, then when he returns to the cell, he will now select only from doors 2 and 3.) (c) for parts (a) and (b), find the variance of the number of days until the prisoner reaches freedom. hint for part (b): define ni to be the number of additional days the prisoner spends after initially choosing door i and returning to his cell.