Answer:
Barlyee's music is 3 times louder than Jessica's.
Explanation:
We know that, loudness is measured as,
![L = 10 * log (I)/(I_o)](https://img.qammunity.org/2019/formulas/mathematics/high-school/ou1u90cp2l09z4v30gct6bgs11c2kphb3j.png)
So let us measure the loudness of music that Jessica is listening to,
![L = 10 * log (10^(-9))/(10^(-12))=10 * log {10^3}= 10 * 3 log 10= 30 dB](https://img.qammunity.org/2019/formulas/mathematics/high-school/sgdoufx79jxy30lls8wih3et106xjpnipo.png)
So Jessica is listening to music at 30dB.
And the loudness of music that Barylee is listening to,
![L = 10 * log (10^(-3))/(10^(-12))= 10 * log {10^9}= 10 * 9 log 10= 90 dB](https://img.qammunity.org/2019/formulas/mathematics/high-school/3x36tgkjnfri9bf1onj9byxu6s4qirt1ms.png)
So Barylee is listening to music at 90dB.
![90=3 * 30](https://img.qammunity.org/2019/formulas/mathematics/high-school/h8kftumkrvp42a4gnfvp2o64b15r7ifg92.png)
Therefore, the music that Barylee is listening to, is 3 times louder than the music Jessica is listening to.