Notice that:
[tex]\begin{gathered} 25=5\cdot5, \\ 27=3\cdot3\cdot3. \end{gathered}[/tex]Then 25 and 27 have no common factors.
Since the denominator and the numerator have no common factors, then the given fraction is in its simplest form.
Answer: 25/27.
[tex]\frac{25}{27}\text{.}[/tex]