This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

At least forty years after Joash became king of Judah.

2 Kings 13:1 View context

In the three and twentieth year of Joash the son of Ahaziah king of Judah Jehoahaz the son of Jehu began to reign over Israel in Samaria, [and reigned] seventeen years.

In the thirty seventh year of Joash's reign.

2 Kings 13:10 View context

In the thirty and seventh year of Joash king of Judah began Jehoash the son of Jehoahaz to reign over Israel in Samaria, [and reigned] sixteen years.