When a buyer and seller have signed a purchase contract, it is classified as which type of contract?

A purchase contract signed by both a buyer and a seller is classified as an expressed contract because it involves clear, definitive terms that have been mutually agreed upon by both parties. In an expressed contract, the intentions and commitments of the parties are explicitly stated, which is the case when a purchase agreement is drafted and signed. This type of contract is generally documented in writing, specifying the details of the sale, the price, and the responsibilities of both parties.

The other types of contracts mentioned have different characteristics. A unilateral contract involves a promise from one party that is not contingent upon an agreement from the other party, which does not apply in this situation. An implied contract is formed through the behavior of the parties rather than through written or spoken words, which again does not fit a signed purchase contract. Contract by estoppel arises from situations where one party is prevented from claiming something contrary to what is implied by their previous actions or statements, which does not apply to a formally signed agreement.