How did Sai Baba prove to Dev that he had attended the Udyapan feast?

Sai Baba proved his attendance by revealing the specific details of his visit, which Dev had failed to recognize. According to Chapter 40, when Jog relayed Dev's complaint, Baba explained that he had indeed come in the guise of a Sanyasi. He clarified, "I said I would come with two others, and I went with two others." Baba pointed out that he had first appeared alone as a Sanyasi and then returned at noon with two companions for the meal, exactly as promised. Baba's account, which Jog then sent to Dev in a letter, perfectly matched the events of the day, forcing Dev to realize his mistake and that the failure was in his perception, not in Baba's promise.