Final answer:
A contract like the one between Steve and Gloria can be rescinded if there is a mutual mistake of fact that is material, significantly affecting the contract's terms or performance.
Step-by-step explanation:
Steve and Gloria's contract for the sale of an office building can only be rescinded due to a mutual mistake of fact if the mistake is material. A material mistake of fact is a misunderstanding that is significant enough to impact the agreement in such a way that it would alter the parties' performances or the value of what they are contracting for. This means that a party cannot rescind a contract based on a mistake that is immaterial or insignificant to the agreement.