The skeptic's confusion:

He was 18 years old when he began to reign and he reigned for 3 months.

"Jehoiachin was eighteen years old when he began to reign, and he reigned in Jerusalem three months." 2 Kings 24:8

He was 8 years old when he began to reign and he reigned for 3months and 10 days.

"Jehoiachin was eight years old when he began to reign, and he reigned three months and ten days in Jerusalem." 2 Chronicles 36:9

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Explanation:

This is simply a copyists error. The passage should read eighteen years old. As far as the length of his reign, the three months are rounded off in 2 Kings.

"And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you that which shall befall you in the last days... Dan shall judge his people, as one of the tribes of Israel. Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward. I have waited for thy salvation, O LORD." Genesis 49: 1, 16-18