By your cell phone contract, you pay a monthly fee plus $0.03 for each minute you spend on the phone. In one month, you spent 240 minutes over the phone, and had a bill totaling $26.20.

Question

Let x be the number of minutes you spend on the phone in a month, and let y be your total cell phone bill for that month. Use a linear equation to model your monthly bill based on the number of minutes you spend on the phone.

a.) Slope intercept equation
b.)If you spend 150 minutes on the phone in a month, you would be billed?
c.) If your bill was $31.90 one month, you must have spent _____
minutes on the phone in that month.

Answer 1

If the fee is f, then
y = f + .03x
You know that
f + .03*240 = 26.20
So, find f, and then use that to work the rest