Question 4
John wrote a 3-digit number on a piece of paper and asked Peter to guess it. Peter asked: “Is the number 892?” John replied: “One of the digits is correct, the position of that digit is also correct.” Peter asked again: “Is the number 178?” John replied: “Two digits are correct, but the positions of those digits are both wrong.” Peter asked again: “Is the number 785?” John said: “All three digits are correct, but the digits are all in the wrong places.” What is the number written by John?
