I request a hint, clarification (if needed), or your approval (if my doutful solution is correct) for this problem:
Problem 9. Peter said: "The day before yesterday I was 10, but I will turn 13 in the next year." Is this possible?
Every hint or clarification you propose is really acknowledged. Here's the link of the book in case you need it.
Here's my doubtful (incomplete) solution (try):
I was thinking about leap years. So the foundation of the solution is that Peter was born on February 29th. For example, consider the time interval from 2016 and 2020. Suppose that his 20th birthday is on Febuary 29th. In any other month in 2019, he could say that he's still 20 years old, and next year he will turn 24.
I think the main idea may be there. However, I get lost when "the day before yesterday" is said.
Moreover, I cannot realize any ideas outside the idea of the leap year. There's no way you can talk about a person that's 10 years old and next year is 13.
Thank you very much!
P.S. You may note that the book has a section of answers and hints. However, I eagerly wish to discuss the problem, and solve it (being given your approval) without seeing the answer. Without seeing the answer and receiveing feedback, I own the possibility of re-thinking my answer, refining it, and improving my mathematical thinking. This is by far the most important exercise for me.
P.S.S. I am not an English-native speaker, so every correction to my writing is really appreciated!
