m = number of months
Option 1 cost = 35 + 20m
Option 2 cost = 25m
Part 1: If the cost is equal for both otpions, then we can write: 35 + 20m = 25m, solving for m:
5m = 35 ==> m = 35/5 = 7
m = 7
In month 7, the cost is 35 + 20(7) = 35 + 140 = 175
Part 2:
Option1 cost when m = 11: 35 + 20(11) = 35 + 220 = 255
Option2 cost when m = 11: 25(11) = 275
Option 2 costs more than option 1, so Option 1 is cheaper
