Question

question is in image

Answer 1

To find the answer, we have to find the slope of the line.

$m=\frac{y_2-y_1}{x_2-x_1}$

Let's replace the points (2,20) and (8,80), where

$\begin{gathered} x_1=2 \\ x_2=8 \\ y_1=20 \\ y_2=80 \end{gathered}$$m=\frac{80-20}{8-2}=\frac{60}{6}=10$

This means that the tip earned increases at a rate of $10 per hour.

Hence, the correct answer is B.