We have the following:
The first thing is to transform the mixed numbers to decimal numbers, in the following way:
[tex]\begin{gathered} \frac{2}{3}=0.67 \\ 2\frac{5}{6}=2.83 \end{gathered}[/tex]a.
to calculate the remaining time we must subtract the times where music is heard from 6 hours
[tex]6-0.67-2.83=2.5[/tex]Therefore, the answer is 2.5 hours or 5/2 hours battery remaining
b.
To calculate the fraction we must calculate that it represents 2.5 or 5/2 hours in the total, that is, 6 hours
[tex]\frac{\frac{5}{2}}{6}=\frac{\frac{5}{2}}{\frac{6}{1}}=\frac{5\cdot1}{6\cdot2}=\frac{5}{12}[/tex]The diagram is: