Required Mathematical Intelligence

Chapter 91 The Bell
Xiao Ming's house is very close to the train station, and he can get up every day according to the bell of the station building.For the clock of the station building, the delay is 3 seconds after each ringing, and the second ringing is after an interval of 1 second.

If Xiao Ming wakes up from the first ringing of the bell, then how many seconds have passed since Xiao Ming clearly judged that it was 6:[-] in the morning?
[答案：从第一下钟声响起，到敲响第6下共有5个“延时”、5个“间隔”，共计（3 1）×5=20秒。当第6下敲响后，小明要判断是否清晨6点，他一定要等到“延时3秒”和“间隔1秒”都结束后而没有第7下敲响，才能判断出确是清晨6点。因此，答案应是：

(3 1)×6=24 (seconds). ]
(End of this chapter)