How can one help reduce corruption?

Question:

A group of ten people traveling in a bus from station A to Station B. The fare is Rs. 10/person with the total fare Rs. 100. But, the ticket master instead asks the group to pay only Rs. 50 and travel without tickets. He gives the assurance that the checking squad will not charge them for traveling without tickets. Here, the ticket master and checking squad know each other and will distribute the Rs. 50 among themselves, with an ultimate loss of Rs. 100 to state transportation and the people involved in this corruption go unnoticed. How can one prevent this economic loss to the state?

Answer:

You could allow the group to report this to the station master and get a Rs. 25 award. You could randomly check buses unannounced. You could offer a bonus to the ticket master for every ticket he has proof of having sold.