That's the answer and the explanation I got, too. 98. The ones digit is the one on the right, and the tens digit, which would be 9 because it has one more than 8, is the one one on the left. (If there were a hundreds digit, it'd add another level onto the left side.)

I'm not stoned, if that helps affirm the answer. Can you sort of walk your little sister through that answer to help her understand why you arrived at 98 instead of just writing it down for her? We do want her to get some learning out of the question!