Question

Please help with this . I am really stuck on it.The graph shows how time required to ring up a customer is related to the number of items being purchased.If it takes 80 seconds to ring up a customer, how many items are purchased?

Answer 1

First, we have to find the slope of the line. Let's use the points (30, 60) and (40, 80). Using the slope formula, we have.

`m=(y_2-y_1)/(x_2-x_1)`

Let's replace the points.

`m=(80-60)/(40-30)=(20)/(10)=2`

Then, we use one point, the slope, and the point-slope formula to find the equation.

`\begin{gathered} y-y_1=m(x-x_1) \\ y-60=2(x-30) \\ y-60=2x-60 \\ y=2x-60+60 \\ y=2x \end{gathered}`

Then, we use this equation to find the items purchased for 80 seconds.

`y=2\cdot80=160`

Therefore, if it takes 80 seconds to ring up a customer, the number of items purchased is 160.