Question

By your cell phone contract, you pay a monthly fee plus some money for each minute you use the phone during the month. In one month, you spent 230 minutes on the phone, and paid $17.45. In another month, you spent 370 minutes on the phone, and paid $19.55.
Let x be the number of minutes you talk over the phone in a month, and let y be your cell phone bill for that month. Use a linear equation to model your monthly bill based on the number of minutes you talk over the phone.
a) This linear model’s slope-intercept equation is

b) If you spent 150 minutes over the phone in a month, you would pay

c) If in a month, you paid $21.50 of cell phone bill, you must have spent
minutes on the phone in that month.

Answer 1

It would take 500 minutes for the cost to be $21.50.

Linear equation

A linear equation is in the form:

y = mx + b

where y, x are variables, m is the rate of change (slope) and b is the y intercept.

Let y represent the cell phone bill for x minutes. Using points (230, 17.45) and (370, 19.55):

$y-y_1=\frac{y_2-y_1}{x_2-x_1} (x-x_1)\\\\y-17.45=\frac{19.55-17.45}{370-230} (x - 230)\\\\y=0.015x+14$

For 150 minutes:

y = 0.015(150) + 14 = 16.25

For $21.50:

21.50 = 0.015x + 14

x = 500

It would take 500 minutes for the cost to be $21.50.

Find out more on Linear equation at: brainly.com/question/13763238