The average of and
satisfies
Then
, so if
must be an integer, then the largest integer value it can take on is 19 if
can be a rational number (in which case
) or 18 if
must also be an integer.
Given that none of the provided answer choices lists 18 or 19, I'd bet there's a typo and you're supposed to find the maximum integer value of , in which case the answer would be B as the largest integer value would be 9.