I'm going to use m for minutes Cell carrier 1 0.15 per minute (0.15m) $26.50 first, and then add on for every minute
cost carrier 1 = 0.15m + 26.50
carrier 2 0.25 per minute (0.25m) $14.50 first, and then add on for every minute.
cost carrier 2 = 0.25m + 14.50
to find out when they cost the same, make the two costs equal to each other:
0.15m + 26.50 = 0.25m + 14.50
all that's left is to solve for m
0.15m + 26.50 = 0.25m + 14.50 subtract both sides by 0.15 m 26.50 = 0.2m + 14.50 subtract both sides by 14.50 12 = 0.1 m divide both sides by 0.1 m = 120
the phone carriers will have the same cost at 120 minutes
