Question

The Cumberland Phone Company charges a flat rate fee for the first

100

minutes of phone calls each month. After​ that, there is a charge of

​$0.04

per minute for each minute thereafter. If those calls are outside a local calling​ region, there is a fee of

​$0.16

per minute.

Rosie makes

115

minutes of phone calls. Of the additional 15 minutes of overage​ time, she had

10

minutes outside of her local calling​ area, and

5

minutes inside it.

Assuming that​ 'Y' is the overage charges and​ 'X' is the overage​ minutes, the slope of the curve generated from​ Rosie's overage phone usage is

​(Enter your response rounded to two decimal​ places.)

Answer 1

Answer :

The slope of curve of two variable y and x is given from the equation or also The slope, m, is the change in yi-e  y2 - y1, divided by the change in x i-e x2 - x1).

y=mx +c

where m is the slope and constant coffieicnt c (assuming 0 here )

we get ,

m = y/x or y2-y1/x1-x2

So , lets look at the given data ,

we have ,

Average charges

Y1 =​$0.04*5 min. ( local call of 5 minutes ) = $ 0.2

Y2 =​$0.16*10 ( local call of 10 minutes ) =$1.6

Average minutes

X1=5

X2=10

substituting the values in the equation

m = y/x or y2-y1/x1-x2 ,we get

m = ($1.6-$ 0.2)/(10 -5 ) = 0.28 ( positive slope or upward )

Hence the slope of average charges Y and average minutes X is 0.28

which means

Y=0.28X +c

HAVE A GOOD DAY !