Marcos purchases a top-up card for his pre-paid cell phone. his remaining balance, b, can be modeled by the equation b=40−0.1n, where n is the number of minutes he's talked since purchasing the card.
a) how much money was on the card when he purchased it? $ which intercept is this? b-intercept or n-intercept?
b) how many minutes will he have talked when he runs out of money? $ which intercept is this? b-intercept or n-intercept ?
c) what is the slope of this . what are the units on the slope? minute , dollars per minute ,minutes per dollars or dollars ?

Part a) When Marcos purchased the card, the balance on the card was $40

This is the B-intercept

Part b) Mark will have spoken 400 minutes when he runs out of money

This is the n-intercept

part c) The slope of the equation is -0.1 and the units are dollars per minute

Step-by-step explanation:

we have

where

B is balance in dollars on the card

n is the number of minutes

Part a) How much money was on the card when he purchased it? $______. Which intercept is this? B-intercept or N-intercept?

we know that

The B-intercept is the value of B when the value of n is equal to zero

so

For n=0

substitute and find the value of B

therefore

When Marcos purchased the card, the balance on the card was $40

This is the B-intercept

Part b) How many minutes will he have talked when he runs out of money? $_____. Which intercept is this? B-intercept or n-intercept ?

we know that

The n-intercept is the value of n when the value of B is equal to zero

so

For B=0

substitute and find the value of n

therefore

Mark will have spoken 400 minutes when he runs out of money

This is the n-intercept

Part c) What is the slope of this equation?________ . What are the units on the slope? Minute , dollars per minute ,minutes per dollars or dollars ?

we have

This is is the equation of the line into slope intercept form

-----> slope of the equation

------> the B-intercept

The units of the slope are dollars per minute

12*c

step-by-step explanation:

company a

step-by-step explanation:

using the linear regression models , it is found that company a   pays about $14 more. but using the same regression (linear) company b pays about $10 more.

so company a pays more than b