Frequently, real estate contracts are conditioned on an event such as the buyer’s ability to sell his current home by a certain date. If the home does not sell, the condition does not arise, and the parties have no duty to perform and are thus discharged from the contract. This is an example of a contract that is subject to a .

Ray gives his son, mason, three bowls. these bowls have the same capacity, but each one differs slightly in its shape and size. ray tells his son that one of the bowls can hold more liters of oil than the other two bowls. mason points out that all the bowls, though may appear different in size and shape, can store the same volume of oil. in this case, ray was most likely testing mason's concept of