Let $X$ be a two-digit number and $Y$ be another two-digit number formed by interchanging the digits of $X$ . If $(X+Y)$ is the greatest two-digit number, then what is the number of possible values of $X$ ?

Kepler. Discussing PYQs. Q.no. 35

Let XXX be a two-digit number and YYY be another two-digit number formed by interchanging the digits of XXX . If (X+Y)(X+Y)(X+Y) is the greatest two-digit number, then what is the number of possible values of XXX ?