Answer with explanation:
Amount of free time Ana has =
![(1)/(2)\text{ hour}](https://img.qammunity.org/2020/formulas/mathematics/high-school/2eou8k387b4souypra420zmi3i4n4ot3yx.png)
If she divides the time equally between walking her dog and playing her favorite song on the piano, then time she spends on playing her favorite song on the piano = (Free time) ÷ 2
hour
i.e. Time she spends on playing her favorite song on the piano =
hour
If she plays the song 3 times , then the length of each song (x) =
![(\text{Time she spend to play her song})/{3}](https://img.qammunity.org/2020/formulas/mathematics/high-school/3yj4h4qlrr64cd2rhlk2wf8eildkcfz3gw.png)
![\Rightarrow\ x=(1)/(4)/ 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/8f6fu125h7ix3kr37jh4wuw4rsjomh7bap.png)
![\Rightarrow\ x=(1)/(4)*(1)/(3)=(1)/(12)](https://img.qammunity.org/2020/formulas/mathematics/high-school/pyx3xi8oef8jx3l4k7t6mkcao0ol589d3q.png)
Hence , the length of the song is
hour.