There are two unevenly distributed fragrances. The incense burning time is one hour. How can you determine a period of 15 minutes?

This seems to be a very classic smart question.

What is behind the smart question is a full understanding of the problem.

First, incense is unevenly distributed, that is to say, there is no relationship between the burning time and the length; in addition, the two incense is the same; third, I just asked you to determine a period of 15 minutes, and didn't let you specify the time from which part of the incense to which part is 15 minutes. There are no other tools, and only one incense burner is burned for one hour.

You may also know the solution to this question.

First, ignition one end of incense, and ignition the two ends of another incense, when the two ends of incense burn out, it is half an hour; when the two ends of incense burn out, ignition of the other end of the remaining fragrance. In this way, from the other end of the remaining fragrance to the final burnout, it will take 15 minutes.

I believe most people can come up with a solution.

Solving problems is a kind of realm, but the talents who come out of this question are at a higher level.