We have to find how many minutes she need to spend on her 6th ride to have an average of 55 minutes.
If we call t to the time she spends on the 6th ride, we can express the average as the sixth part of the sum of the times:
[tex]\frac{46+63+56+56+55+t}{6}=\frac{276+t}{6}[/tex]We can equal this result to 55 minutes and find t as:
[tex]\begin{gathered} \frac{276+t}{6}=55 \\ 276+t=55*6 \\ 276+t=330 \\ t=330-276 \\ t=54 \end{gathered}[/tex]Answer: she needs to spend 54 minutes on the 6th ride for the average to be 55 minutes.