This question is to be struck at five o'clock sharp (that is, when the pointer reaches 12), which is also in the last eighth second. This is the problem of planting trees at both ends.

Five strokes belong to a tree, and eight seconds is the total length of the pointer.

So: 8÷(5- 1)=2 (indicating the interval, that is, knocking every two seconds)

12 point, knock 12 to indicate a tree with an interval of 2, and find the total length.

(12- 1)×2=22 (seconds), and the correct answer is 22 seconds.