when a product is purchased it must be capable of fulfilling its function a new refrigerator must keep food cool or either the manufacturer or the seller has failed to meet the terms of an implied contract 
an implied contract is sometimes difficult to enforce because proving the justice of the claim is a matter of argument not a simple matter of producing a signed document in addition some jurisdictions place limits on implied contracts for example a contract for a real estate transaction must be backed up by a written contract in some courts an implied contract has the same legal force as a written contract but may be harder to enforce implied in fact vs implied in law contractsthere are two forms of implied contract called implied in fact and implied in law contracts an implied in fact contract is created by the circumstances and behavior of the parties involved if a customer enters a restaurant and orders food for example an implied contract is created the restaurant owner is obligated to serve the food and the customer is obligated to pay the prices listed on the menu for it an implied in fact contract may also be created by the past conduct of the people involved for example a teenager offers to walk a neighbor s dog and is rewarded with two movie tickets on three subsequent occasions the teenager comes over to walk the dog and is given two movie tickets but on the last occasion the neighbor simply fails to produce the movie tickets the teenager has a case for claiming that the neighbor created an implied in fact contract by regularly producing movie tickets in return for dog walking services it is a reasonable assumption the following must be present to establish an implied in fact contract the other type of unwritten contract the implied in law contract can also be called a quasi contract it is a legally binding contract that neither party had the intention of creating say the same restaurant patron mentioned above chokes on a chicken bone and a doctor dining at the next booth leaps to the rescue the doctor is entitled to send a bill to the diner and the diner is obligated to pay it 