(1) If there are several persons who have accomplished the act specified in the advertisement, the person who accomplished it first shall be entitled to the reward.
(2) If two or more persons have accomplished the act simultaneously, each of them shall be entitled to the reward in equal proportions; provided, If the reward is by its nature indivisible, or if it has been stipulated in the advertisement that only one person is to receive the reward, the ultimate recipient of such a reward shall be determined by drawing lots.