48.When a mistake occurs as to the market value of the object of a contract

a.either party can enforce the contract.

b.either party can enforce the contract if the mistake if not more than 20% of the true market value.

c.either party can rescind the contract for failure of consideration.

d.the contract is enforceable by either party if the object of the contract is tangible personal property but not real property.

49.When the offeror and offeree of a contract are mistaken as to the same material fact

a.either party can rescind the contract at any time.

b.both parties must agree to rescind the contract.

c.either party can rescind the contract but only if done so promptly

d.there can be no recission if it is a third party beneficiary contract.