ABC:2 Kings 24

Verse 8
Jim Meritt of Infidels states a contradiction exists here, asking "How old was Jehoiachin when he began to reign?" TheThinkingAtheist also claims there is a contradiction here. So too do Wikipedia and RationalWiki. Comments by the critic are italicized.

2 Kings 24:8 Jehoiachin was eighteen years old when he began to reign, and he reigned in Jerusalem three months. And his mother's name was Nehushta, the daughter of Elnathan of Jerusalem.

2 Chronicles 36:9 Jehoiachin was eight years old when he began to reign, and he reigned three months and ten days in Jerusalem: and he did that which was evil in the sight of the LORD.

Although at first glance this appears to be a case of scribal error, the reality is that both passages are correct. Jehoiachin actually began to reign in Judah at age 8 (2 Chronicles 36:9) and in Jerusalem at age 18 (2 Kings 24:8).

For a more detailed (and excellent) explanation of this, see KJV Today. As KJV Today points out:

"Jehoiachin’s co-regency of ten years corresponds perfectly with his father Jehoiakim’s reign of eleven years (2 Chronicles 36:5). Moreover, as soon as the Babylonian invasion looms into the picture, Chronicles begins to use the phrase, 'king over Judah and Jerusalem' (2 Chronicles 36:4, 10)." -KJV Today

This is a case of an apparent discrepancy being explained by a complex situation, with all the evidence coming together perfectly (as beautifully explained by KJV Today) to make crystal clear what was occurring.

10 Days?
TheThinkingAtheist.com in its aforementioned accusation also takes exception to the passages differing in how long Jehoiachin was said to reign in Jerusalem, noting for 2 Kings 24:8, "18 years old. Reigned three months." and for 2 Chronicles 36:9, "8 years old. Reigned 3 months and 10 days." Logically there is no contradiction, since he reigned both 3 months and 3 months and 10 days assuming the second is the correct answer. In all probability, the first was just rounding and the second a more exact number. Both therefore are correct, the second just gave additional detail.

Many Biblical accounts when saying someone reigned for X years, for example, are not mentioning how many months or days, but just giving the number of years, as they would not keep track of the exact number of months, days, hours, or minutes. The first account was then simply giving time in number of months, and never mentioned the days as did the second account. Rather than a contradiction, it's just a matter of additional detail.