Answer:
The instructor’s initial charge is $20
see the attached figure
Step-by-step explanation:
Let
x ----> the time in hours
y ----> the total cost in dollars
we know that
The linear equation in slope intercept form is equal to
where
m is the slope or the unit rate of the linear equation
b is the y-intercept or initial value (in this problem is the instructor’s initial charge)
we have
The slope is equal to the hourly rate
so
substitute
To find out the y-intercept join the given points in the graph and find out the value of y when the value of x is equal to zero
see the attached figure
The y-intercept is the point (0,20)
therefore
The instructor’s initial charge is $20
<u><em>Verify</em></u>
take any point on the graph
(5,60)
For x=5, y=60
substitute in the linear equation and solve for b
----> is ok
therefore
The instructor’s initial charge is $20
