Old Faithful is a geyser in Yellowstone National park that erupts according to an arithmetic sequence. The first eruption of the day occurred at 12:00 am. Suppose that you are in the park and you know that the latest eruption, which was at 12:22 pm, was the 4th eruption of the day.

[A] What is the common difference?
[B] When can you expect the geyser to erupt next?