Question

Maria went to the restaurant and waited 90 seconds to place her order. Use the trend line equation to predict how many employees were working. Round to the nearest whole number if necessary.​

Answer 1

3 employees

Explanation:

The complete question is

The manager of a fast food restaurant collected data to study the relationship between the number of employees working registers and the amount of time customers waited in line to order. He made a scatter plot of the data and created a trend line with the equation y = -70x + 300, where y is the total amount of time waited in seconds and x is the number of employees working registers. Maria went to the restaurant and waited 90 seconds to place her order. Use the trendline equation to predict how many employees were working. Round to the nearest whole number if necessary.

Let

x ---> is the number of employees working registers

y ---> is the total amount of time waited in seconds

we have

`y=-70x+300`

This is the equation of a line in slope intercept form

where

The slope is equal to

`m=-70\ (seconds)/(employee)` ---> is negative because is a decreasing function

The y-intercept is equal to

`b=300\ sec`

For y=90 seconds

substitute in the linear equation and solve for x

`90=-70x+300`

`70x=300-90\\70x=210\\x=3\ employees`