Can you tell me about the vow a devotee named Cholkar made to Sai Baba and why he made it?

According to Chapter 15, a man named Cholkar came from a poor household where everything depended on his job. To secure his position, he needed to pass an examination, and he felt that his daily bread was at stake. In this desperate situation, he made a firm vow to Sai Baba. He resolved that if he were to pass the examination by Baba's grace, he would present himself at Baba's feet in Shirdi and distribute sugar candy (khadisakhar) in His name. This vow was born out of his need for divine assistance to overcome a critical life obstacle.