One prepaid cell phone company charges $0.029 per minute and a $4 monthly fee. Another company charges $0.034 per minute with no monthly fee. For what number of minutes per month are the charges for the first company cheaper?
We want to solve this inequality
Total cost of 1st company < Total cost of second company
.029 N + 4 < .034N where N is the number of minutes we are looking for
subtract ,029N from both sides
4 < .005N divide each side by .005N
4 / .005 < N
800 < N
The first company will be cheaper after 800 minutes