This Bible contradiction is from the Skeptic's Annotated Bible.
For seven months or so.
Genesis 8:4 View context
And the ark rested in the seventh month, on the seventeenth day of the month, upon the mountains of Ararat.
For at least ten months.
Genesis 8:5 View context
And the waters decreased continually until the tenth month: in the tenth [month], on the first [day] of the month, were the tops of the mountains seen.