A cell phone plan has a monthly cost that is shown in the table below. What is the correct statement regarding the average rate of change during the 40-minute time of talk?

Total minutes of talk time:
0
10
20
30
40
Monthly cost of cell phone:
$19.95
$20.45
$20.95
$21.45
$21.95

The average rate of change is $0.50, meaning that for each minute of talk time, the monthly bill increases by $0.50

The avaerage rate of change is $0.50, meaning that for every ten minutes of talk time, the bill increases by $0.50

Question

A cell phone plan has a monthly cost that is shown in the table below. What is the correct statement regarding the average rate of change during the 40-minute time of talk?

Total minutes of talk time:
0
10
20
30
40
Monthly cost of cell phone:
$19.95
$20.45
$20.95
$21.45
$21.95



The average rate of change is $0.50, meaning that for each minute of talk time, the monthly bill increases by $0.50

The avaerage rate of change is $0.50, meaning that for every ten minutes of talk time, the bill increases by $0.50

anonymous · Answer

The average rate of change is $0.05, meaning that for each minute of talk time, the monthly bil increaes by $0.05

The avaerage rate of change is $0.05, meaning that for every ten minutes of talk time, the bill increases by $0.05

anonymous · Answer

I think it's the second of fourth one, but I'm not sure which one?

tkhunny · Answer

Try First Differences

0 10 20 30 40
10-0 = 10
20 - 10 = 10
30 - 20 = 10
40 - 30 = 10
They are all 10 minutes apart.

$19.95 $20.45 $20.95 $21.45 $21.95
20.45 - 19.95 = 0.50
20.95 - 20.45 = 0.50
21.45 - 20.95 = 0.50
21.95 - 21.45 = 0.50
The all change by 50¢.

Just looking at it, for each 10 minutes of talk time, the bill goes up 50¢.
Dividing both by 10 suggests, for each 1 minute of talk time, the bill goes up 5¢.

Just some hints on one method that might be used to analyze the situation.

anonymous · Answer

y=1/20x + 19.95

tkhunny · Answer

Oh, and get a better User ID.  How do you plan to succeed when you talk about yourself like that?

anonymous · Answer

I think slope-intercept form represents this equation fine.

anonymous · Answer

haha

anonymous · Answer

the slope of 1/20 represents 5cents per minute

anonymous · Answer

So it would be B?
I just came up with something off the top of my head for my ID lol was planning on changing it soon haha

anonymous · Answer

I dont have your choices, therefore, i cannot tell you whether the answer is b or not.

anonymous · Answer

B is The average rate of change is $0.50, meaning that for every ten minutes of talk time, the monthly bill increases by $0.50

anonymous · Answer

It seems like it can be either B or C /:

anonymous · Answer

the average rate of change is indeed 50 cents every ten minutes, equal to 5 cents every minute.