25. In an action for breach of contract by the seller against the girl, the seller's probable recovery is

Some classes of people only have a limited ability to enter into a contract. Typically, these are either infants (i.e., minors) or the mentally handicapped. When a person is a minor, meaning below the age of majority, any contract he enters into may be voidable by him. Thus, the minor can disaffirm or avoid a previous contract before or even soon after he reaches the age of majority (a number that varies by state statute). See Rest. 2d, § 14. An infant may disaffirm a contract before reaching the age of majority or within a reasonable time after reaching majority. When an infant disaffirms and becomes the defendant, meaning he is sued for breach of contract he entered into as a minor, the plaintiff will not be able to recover profits he would have made under the contract or any other contract damages, although he will have a limited right to restitution.

Although typically, one's promise to perform or the actual performance of a pre-existing legal duty is not consideration. However, there is an exception when the obligation was voidable. A promise to perform an obligation that was voidable will be enforceable even without new consideration. For example, an infant may ratify a contract once he reaches majority and it will be enforceable even without new consideration.

C is correct. Normally, promises made in recognition of a past benefit conferred (such as the girl's promise to pay the seller $75) are not enforceable because any benefit received by the girl was not bargained-for (the telescope was not given in exchange for the $75). As an exception to the rule, courts will enforce such a promise if the promisor reaffirms a promise made pursuant to an earlier bargained-for exchange that was not enforceable at the time because of infancy. Although the girl's earlier promise to pay $100 for the telescope was not enforceable because the girl lacked the capacity to contract, her later promise to pay $75 for the telescope is enforceable: first, because the girl no longer lacks the capacity to contract; and second, because her subsequent promise falls within the exception to the rule and is enforceable notwithstanding the lack of consideration.

A is incorrect. The issue presented here is not whether the original contract for $100 in exchange for the telescope was enforceable, but rather, whether her subsequent promise to pay the $75 for the previously-received telescope was enforceable. Her earlier infancy was not dispositive as to the subsequent promise.

B is incorrect. Even though typically a promise to perform a previous legal duty is not consideration, there is an exception when the previous obligation was voidable and is then reaffirmed. Here, the girl's promise to pay $75 after reaching the age of majority falls within this exception, and the court will find sufficient consideration to enforce this promise.

D is incorrect. This is the amount originally promised by the girl before she reached the age of majority. However, only her subsequent promise to pay $75 is enforceable because at the time of that second promise, the girl had reached the age of majority.