A bottle is filled with liquid of which 4 parts are water and 5 parts are fruit extract. How much of the mixture must be drawn off and replaced with water so that the mixture may be half water and half fruit extract?
1
\(\frac{1}{10}\)
2
\(\frac{9}{10}\)
3
\(\frac{4}{9}\)
4
\(\frac{5}{9}\)