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? (1 point)

Answer 1

Second from top...

The average rate of change is $0.07, meaning that for each minute of talk time, the monthly bill increases by $0.07.

Explanation:

Pick any two points and calculate the slope which will represent the rate of change:

(Minutes, Cost)

(0, 9.95)

(10, 10.65)

Rate of change:

slope m = (y₂ - y₁) / (x₂ - x₁)

= (10.65 - 9.95) / (10 - 0)

= 0.7 / 10

= 0.07

y is cost

m is rate of change

x is minute(s) use

b is fixed monthly cost regardless if any minutes is used

y = mx + b

y = .07x + 9.95