Chloe practices soccer for \( \frac{1}{2} \) hour each day. Over 5 days, the total time she spends practicing soccer is calculated as follows:
\[ \text{Total soccer practice} = 5 \text{ days} \times \frac{1}{2} \text{ hour/day} = \frac{5}{2} \text{ hours} = 2.5 \text{ hours} \]
According to the problem, the total practice time for both soccer and flute over the 5 days is 15 hours. Therefore, we can find out how much time she spent practicing flute:
\[ \text{Total flute practice} = \text{Total practice} - \text{Total soccer practice} \] \[ \text{Total flute practice} = 15 \text{ hours} - 2.5 \text{ hours} = 12.5 \text{ hours} \]
Now, to find out how many hours per day she practiced the flute, we divide the total flute practice time by the number of days:
\[ \text{Flute practice per day} = \frac{\text{Total flute practice}}{5 \text{ days}} = \frac{12.5 \text{ hours}}{5} = 2.5 \text{ hours/day} \]
Thus, Chloe practiced flute for
\[ \boxed{2.5} \text{ hours per day.} \]