I can not figure this problem, or others like it, out for the life of me. I have to turn this assignment in 3 hours. Can anyone help?

Question

I can not figure this problem, or others like it, out for the life of me. I have to turn this assignment in 3 hours. Can anyone help?

 

The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes). The remaining credit after
35
minutes of calls is
$14.75
, and the remaining credit after
49
minutes of calls is
$12.65
. What is the remaining credit after
61
minutes of calls?

Callingtimeinminutes
Remainingcreditindollars

Answer 1

As ordered pairs the information is:

(35, 14.75)

(49, 12.65)

The rate of change is 

(12.65 - 14.75) / (49 - 35)

-2.10 / 14

-0.15 / 1

The balance decreases $0.15 for each additional minute.

How many minutes is 61 after 49?

How much does the balance decrease?

What is the balance after 61 minutes?