Problem: Jonah records a “three days’ walk” through the city of Nineveh, but this would make the city larger than even modern cities—let alone ancient ones.
Solution: Jonah did not walk a straight line through the city. He walked through the city and preached at the same time. How could anyone hear his message, if he was walking straight through without stopping? In other words, it was a three days walk, if one includes stopping to preach.