I would really appreciate it if anyone could show their work on this problem as well! Thanks!
Notice that it appears that every month, the total cost increases by $30
And the starting cost = 80 = $50 fixed cost + $30 variable cost
So....letting C be the cost in any month and M be the month, we have that
C = 50 + 30M
When M =4, the total cost , C = 50 + 30 (4) = $( 50 + 120) = $170