Step 1: Assume the original fraction.
Let the original fraction be
\[
\frac{N}{D}
\]
After the changes,
\[
\text{New Fraction}
=
\frac{1.15N}{0.90D}
\]
\[
=
\frac{115}{90}\cdot\frac{N}{D}
=
\frac{23}{18}\cdot\frac{N}{D}
\]
Step 2: Determine the increase factor.
The fraction becomes
\[
\frac{23}{18}
\]
times its original value.
Hence increase factor is
\[
\frac{23}{18}-1
=
\frac{5}{18}
\]
Step 3: Convert into percentage.
\[
\frac{5}{18}\times100
=
\frac{500}{18}
=
\frac{250}{9}
=
27\frac79\%
\]
Therefore,
\[
\boxed{27\frac79\%}
\]