Intellectual problems in recruitment

1) First analyze the 10 group date. It is not difficult to find that there are only two groups of dates: June 7 and 65438+February 2.

Days are unique. Therefore, if Xiao Qiang knows that n is 7 or 2, then he must know the teacher's.

birthday

2) Re-analyze "Xiao Ming said: If I don't know, Xiao Qiang certainly doesn't know" and the date of 10 group.

The number of months is 3, 6, 9, 12 respectively, and there are more than two groups of corresponding month dates, so after Xiao Ming learned about M,

It is impossible to know the teacher's birthday.

3) Combining with Step 2, further analyze "Xiao Ming said: If I don't know, Xiao Qiang certainly doesn't know".

Conclusion: It can be seen that Xiao Qiang will never know after learning N.

4) Combining step 3 and 1, it can be inferred that June and 65438+February are not teachers' birthdays, because

If Xiaoming knows that m is 6 and Xiao Qiang's N==7, Xiao Qiang knows the teacher's birthday. (by the first

Step 1 started). Similarly, if Xiaoming's M== 12 and Xiao Qiang's N==2, Xiao Qiang can also know the teacher's birthday. That is, m is not equal to 6 and 9. Now there are only "March 4th, March 5th, March 8th, September 1".

September 5th "five groups of dates. Xiao Qiang knows, so n is not equal to 5 (there are March 5th and September 5th). At this time,

Xiao Qiang's N ∈ (1, 4,8) Note: Although there are three possibilities for n at this time, it is only necessary for Xiao Qiang to know one of them.

One, you come to the conclusion. So there was "Xiao Qiang said: I didn't know at the beginning, but now I know",

For us, we need to continue to reason.

At this point, the rest may be "March 4th, March 8th, September 1".

5) Analysis of "Xiao Ming said: Oh, I see" shows that M==9, N== 1, (N==5 excluded, there were two groups in March).