Two Internet service providers charge an installation fee plus a monthly service fee. The table shows the total costs in dollars) for different numbers of months at Company A. The total cost $y$ (in dollars) for $x$ months of service at Company B is represented by $y=45x+50$ . Which company charges less per month?
Company A
Months, x Total cost, y
2
3
4
5
6
$180
$220
$260
$300
$340