Long distance cost 1 cent per minute with 3 different carriers. The only difference is Carrier A bills in 1-second increments; Carrier B bills in 6-second increments; and Carrier C bills in 60-second increments.
Which carrier is the lease costly, and by how much over the other 2 competitors?
Assume Carrier B suddenly implements a 30-second minimum (per call) on its 6-second billing. How does this change the math comparing the 3 providers?