Question 24
Chau writes a four-digit number and asks Dung to guess it.
Dung guesses 2896. Chau says: “Exactly one digit is correct, and it is in the correct position.”
Dung guesses 5273. Chau says: “Exactly two digits are correct, but both are in the wrong positions.”
Dung guesses 1702. Chau says: “All four digits are correct, but all are in the wrong positions.”
What number did Chau write?
Dung guesses 2896. Chau says: “Exactly one digit is correct, and it is in the correct position.”
Dung guesses 5273. Chau says: “Exactly two digits are correct, but both are in the wrong positions.”
Dung guesses 1702. Chau says: “All four digits are correct, but all are in the wrong positions.”
What number did Chau write?