Question 23
You have a large strip of paper on which all 20-digit natural numbers are written, ordered from smallest to largest (from $00\ldots01$ to $999\ldots99$) with no spaces between consecutive numbers. Cintia chooses an entero positive number $k$ and tells Elicita. Next, Elicita selects $k$ consecutive digits from the strip of paper, makes a photocopy of the segment of paper that contains these $k$ digits and hands it to Cintia. With this strip of $k$ digits in view, Cintia must determine the exact place on the wide strip of paper where the photocopied segment is located.
There is the lowest value of $k$ that allows Cintia to fulfill the objective, no matter how many $k$ consecutive digits she decides to photocopy Elicita.
There is the lowest value of $k$ that allows Cintia to fulfill the objective, no matter how many $k$ consecutive digits she decides to photocopy Elicita.