Official solution
Let hyperbola is \[{{{x^2}} \over {{a^2}}} - {{{y^2}} \over {{b^2}}} = 1\]
vertices (\[ \pm \]a, 0 ) = (\[ \pm \]6, 0) \[ \Rightarrow \] a = 6
Hyperbola passes through p(10, 16)
\[ \therefore \] \[{{{{10}^2}} \over {{6^2}}} - {{{{16}^2}} \over {{b^2}}} = 1\]
\[ \Rightarrow \] b = 12
\[ \therefore \] Required hyperbola is \[{{{x^2}} \over {36}} - {{{y^2}} \over {144}} = 1\]
Equation of normal will be
\[{{{a^2}x} \over {{x_1}}} + {{{b^2}y} \over {{y_1}}} = {a^2} + {b^2}\]
At P(10,16) normal is
\[{{36x} \over {10}} + {{144y} \over {16}} = 36 + 144\]
\[ \Rightarrow \] 18x + 45y = 900
\[ \Rightarrow \] 2x + 5y = 100