For this case we have that initially the bottle contains [tex]\frac {3} {4}[/tex]of liter of water.
If a person drinks [tex]\frac {1} {2}[/tex] of the contents of the bottle we have:
[tex]\frac {\frac {3} {4}} {2} =\\\frac {3 * 1} {4 * 2} =\\\frac {3} {8}[/tex]
Thus, the person drinks [tex]\frac {3} {8}[/tex] liters of water.
Answer:
The person drinks[tex]\frac {3} {8}[/tex] liters of water.