What was the specific vow Cholkar made to Sai Baba and why did he make it?

As recounted in Chapter 15, Cholkar's vow was born out of desperation for his livelihood. His entire household depended on his job, and to make his position permanent, he had to pass an examination. With his daily bread and candidacy at stake, he made a "firm resolve" and a vow to Sai Baba. He promised that if he passed the exam by Baba's grace, he would come to Shirdi, present himself at Baba's feet, and distribute sugar candy (khadisakhar) in Baba's name. This vow was a direct plea for divine assistance in a critical moment of his professional life.