Question 98396
Suppose that the monthly cost of a long-distance phone plan (in dollars) is a linear function of the total calling time (in minutes). When graphed, the function gives a line with a slope of 0.09. 
The monthly cost for 44 minutes of calls is $17.80. What is the monthly cost for 37 minutes of calls? 
--------------
cost = (slope)minutes + (constant)
17.80 = 0.09(44)+ constant
constant = $13.84
-------------------
EQUATION:
cost = 0.09(minutes)+13.84
What is the monthly cost for 37 minutes of calls? 
cost = 0.09(37) + 13.84
cost = 3.33 + 13.84
cost = $17.17
===================
Cheers,
Stan H.