Answer:
45 miles
Explanation:
Let x represent the miles Lisa needs to hike on the last day.
Given the miles she biked on the first 5 days as 49,57,52,50 and 53 and her average(mean) per day as 51 miles per day.
We can go ahead and determine x using the mean formula and substituting the given values into the formula as seen below;
[tex]\begin{gathered} Mean=\frac{\text{Sum of the terms}}{\text{Number of terms}} \\ 51=\frac{49+57+52+50+53+x}{6} \\ 51=\frac{261+x}{6} \end{gathered}[/tex]Let's cross-mulitply;
[tex]\begin{gathered} 261+x=51\cdot6 \\ 261+x=306 \\ x=306-261 \\ x=45\text{ miles} \end{gathered}[/tex]We can see from the above that Lisa needs to bike 45 miles on the last day so that her average(mean) is 51 miles per day.
