There are No.1 bus and No.9 bus. They come every 10 minutes. Three minutes after No.1 bus leaves, No.9 bus comes. Seven minutes later, No.1 bus comes Which bus is the most likely?

There are No.1 bus and No.9 bus. They come every 10 minutes. Three minutes after No.1 bus leaves, No.9 bus comes. Seven minutes later, No.1 bus comes Which bus is the most likely?

Three minutes after the No.1 bus left, the No.9 bus came. Seven minutes later, the No.1 bus came
The time is 1-3 minutes. Wait until bus No.9,
And 3-10 minutes, wait for the No.1 bus
So it's more likely to wait until the No.1 bus