I missed this problem when I took my GPrep 1 exam.
K is either going to be negative or positive. Since it's a constant, it will always be the same number.
Statement 1 does not give us the means to solve K.
Statement 2 does not either. But since, as gmatutor has pointed out, the term given in this statement is in the middle of our terms, it doesn't matter. Since K isn't zero, it has to give us a linear sequence. If K = 1, and term 8 = 10, then term 9 = 11, term 10 = 12, and so forth. Meanwhile, term 7 = 9, term 6 = 8, etc.
If K = -1, then term 9 = 9, term 10 = 8; term 7 = 11, term 6 = 12, etc.
Either way, we'll get 7 terms that are > 10.