Answer:
Option C is correct
$120
Step-by-step explanation:
The equation of best line is given by:
....[1]
where, y represents the total amount of money earned in tip after x hours, m is the slope and b is the y-intercept.
As per the statement:
From the graph:
Two points are:
(2, 20) and (8, 80)
Formula for slope(m) is given by:

then;

⇒m = 10
Substitute in [1] we have;

Also , substitute the point (2, 20) to find b;

⇒
Subtract 20 from both sides we have;
⇒0 = b
or
b = 0
Then, we get the equation:

We have to find total amount of money earned in tips after working 12 hours.
⇒x = 12 hours
then;

Therefore, the total amount of money earned in tips after working 12 hours is, $120