Telecommunication Industry.

In determining the validity of a contract, it is important to determine the

length of the contract. A telecommunication company arranges for a prepaid, month$-$to$-$month, cellular

contract with a customer. The customer pays for a month of cellular service on the $$rst day of the service

period. A typical customer will remain on the month$-$to$-$month contract for a two$-$year period. In evaluating

the validity of a contract, what is the length of contract?