Final answer:
When Linda is adjudicated incompetent and has a guardian appointed, any contract she enters, including purchasing a car, is void due to her lack of legal capacity.
Step-by-step explanation:
Linda is adjudicated incompetent by a court and a guardian is appointed, but she subsequently purchases a new car. The contract is void. When an individual is declared legally incompetent and a guardian is appointed, they generally do not have the legal capacity to enter into binding contracts. Legal capacity is a prerequisite for enforceable contracts, and without it, contracts are not valid. The idea that a person must be able to understand and agree to the terms of a contract is fundamental in contract law. Therefore, Linda's mental incompetence as determined by the court means that she lacks this capacity, making any contract she enters into void.