Calculating Average Wait Time for a McDonald's Drive-Through Window

In summary, Queuing Theory states that for a drive through window at a McDonald's, the average waiting time in hours for a customer can be represented by the function f(x) = 9/(x(x-9)), where x is the average number of people per hour. To find the average waiting time, the average of the function over a given range can be calculated using the formula \frac{\int_a^b f(x)dx}{b-a}.
  • #1
tachu101
74
0

Homework Statement


Queuing Theory (study of lines for stores) says that for a drive through window at a Macdonalds, the function

f(x)= 9/(x(x-9))

represents the average time in hours a customer will wait in line. X=average number of people an hour.
How long will a customer have to wait in line (on average)?

The Attempt at a Solution



Not sure at all on how to find an average time out of this function.
 
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  • #2
Were you given a value for x?
 
  • #3
The question I think says 9<x<or=20
 
  • #4
Yes, x will have to be larger than 9 for that function to be positive- and I've never had a negative waiting time at McDonald's! The average of a function, f(x), over [itex]a\le x\le b[/itex] is
[tex]\frac{\int_a^b f(x)dx}{b-a}[/tex]
 

What is a rational function?

A rational function is a function that can be written in the form of f(x) = P(x)/Q(x), where P(x) and Q(x) are polynomials. In other words, it is a function that is the ratio of two polynomial functions.

What is the domain of a rational function?

The domain of a rational function is the set of all real numbers except for those values of x that make the denominator Q(x) equal to zero. These values are called the vertical asymptotes of the function.

How do you simplify a rational function?

To simplify a rational function, factor both the numerator and denominator, and then cancel out any common factors. This will result in a simplified form of the function.

What is the relationship between rational functions and asymptotes?

Rational functions can have both vertical and horizontal asymptotes. The vertical asymptotes occur when the denominator of the function is equal to zero, while the horizontal asymptotes occur when the degree of the numerator and denominator are equal. The horizontal asymptote can also be found by dividing the leading coefficients of the numerator and denominator.

How do I find the x and y intercepts of a rational function?

To find the x-intercepts, set the function equal to zero and solve for x. To find the y-intercept, substitute in x = 0 and solve for y. Keep in mind that rational functions may not have x-intercepts, but they will always have a y-intercept at (0, c), where c is the constant term in the function.

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