Ningbo Chengxiang Bus Company driver Yao Jiangwei still can't believe what happened.

Early in the morning on May 16, in Ningbo, E. Zhejiang Province, an elderly woman, accompanied by a younger man and woman, boarded Yao's bus and quickly slid a wad of money into the coin box. Through the glass he could see they were all 100-yuan notes.

"It was early in the morning, and I thought I must be tired. I have never seen anything like it, " says Yao. He called his company immediately and reported the incident.

"I was told to keep a close eye on the three passengers, and then drive directly to the bus terminal after the first completion of the route," Yao says.

Back in the bus terminal, Yao found out that he wasn't the only one to find a wad of notes in his coin box. The bus company's security manager, Zhou had had the same experience.

"While checking the coin box on Tuesday, we saw exactly the same thing, 12 100-yuan notes. We were shocked. We thought some passenger had made a mistake. We'd been trying to figure it out," Zhou says.

After talking to Yao, Zhou realized the elderly woman on the bus might be the mysterious passenger he had been looking for. After a brief search, Zhou's hunch was confirmed.

The three mystery passengers were found to be a mother and her children from a village in Ninghai County, Zhejiang Province.

According to the woman, she had wanted to see one of her daughters in Beijing. Thinking that every bus could take her there, she randomly boarded a bus in Ningbo with no idea how much it cost for a ride.

Her son told her it cost about 400 yuan per person ($US50) to get to Beijing, so she put 1,200 yuan ($US150) into the bus's coin box to pay for their trip.

Her youngest daughter, who lives in Ningbo, was soon informed of the matter, and explained to local police that her mother, elder brother and sister were uneducated and seldom left the village.

All the money was returned.