53:28 Nathan and Jordan design surveys to determine the average amount of time bicyclists in a race spend training each
week. Nathan surveys every fifth bicyclist crossing the finish line after a race. Jordan surveys the first five bicyclists to
finish the race. Which best explains which sample is likely to be the most valid?
Nathan's because his sample was more random
Jordan's because his sample was more random
Nathan's because his sample contained elements of the population
Jordan's because his sample contained elements of the population

Nathan's because his sample was more random  

Step-by-step explanation:

Nathan's survey could be described as a Systematic random sampling technique whereby every 5th observation taken as a sample from the population. With these technique we have a more random observation than with.

answer: was that a question or answer?

step-by-step explanation:

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204