Answer :
she needs to spend 61 minutes in her seventh ride
ExplanationThe average of a set of numbers is simply the sum of the numbers divided by the total number of values in the set.
so
[tex]average=\frac{sum\text{ of the data}}{number\text{ of values}}[/tex]Step 1
so
a)let x represent the time she spent on her seventh ride
hence
[tex]\begin{gathered} sum\text{ of data=48+56+41+49+43+59+x} \\ number\text{ of values=7} \\ average\text{ time=51} \end{gathered}[/tex]b) now, replace and solve for x
[tex]\begin{gathered} average=\frac{sum\text{ of the data}}{number\text{ of values}} \\ 51=\frac{48+56+41+49+43+59+x}{7} \\ 51=\frac{296+x}{7} \\ Multiply\text{ both sides by 7} \\ 51*7=\frac{296+x}{7}*7 \\ 357=296+x \\ subtract\text{ 296 in both sides} \\ 357-296=296+x-296 \\ 61=x \end{gathered}[/tex]therefore, the answer is
she needs to spend 61 minutes in her seventh ride
I hope this helps you