Ashley says to Bob: "I promise to pay you $20 if you shovel my sidewalk." Bob begins to shovel,and he soon completed 90% of the job.Then Ashley tells him: "Thanks,but I revoke." Bob then finishes the job in about ten minutes.Can Bob recover against Ashley in contract? Why or why not? In any event,what other theory might Bob use? Assume that an offer for a unilateral contract is accepted by full performance of the requested act.

Bob can recover against Ashley in contract because he accepted by fully performing.Ashley's attempted revocation would be ineffective for one or more of the several reasons stated in the text.Perhaps the most widely accepted is the rule that when the offeree begins performance,he suspends the offeror's power to revoke for a reasonable time to complete performance.Furthermore,once the offeree begins performance,a bilateral contract is formed.In any event,Bob could recover under quasi-contract for at least the 90% of the job that he completed before Ashley's attempted revocation.Ashley was enriched,she was aware of that fact at the time of enrichment,and it almost certainly was unjust for her to benefit without paying Bob.