The cost of a long-distance telephone call is given by the function
C(m) = 0.15m + 1

where m is the length of the call in minutes. What does the slope represent?

A. cost per minute
B. length of call
C. connection cost
D. cost of having a phone line

Question

The cost of a long-distance telephone call is given by the function
C(m) = 0.15m + 1

where m is the length of the call in minutes. What does the slope represent?

A. cost per minute
B. length of call
C. connection cost
D. cost of having a phone line

badhi · Answer

if you find an equation like $$y(t) = at +b $$ or any expression with time being the independent variable (t for the x axis) the slope always says the rate of change of y(t) 

so if y is the water level of a tank the slope of that expression means the rate of change of the water level. or if y happen to be the distance of a vehicle the slope will be the rate of change of the distance which is also called the speed of the vehicle. So i guess you can find the answer if y(t) happend to be the cost of the telephone call ;)