1. Carl's constant rate of speed is the slope of the straight line graph.
This straight line passes through: (0,0), (5,1), (10,2) etc
We can use the slope formula with any two points to find the slope of this line.
The slope formula is
.
Let
and

Then
,
.
Carl's speed is
miles per minute.
But we must leave our answer in miles per hour
Hence Carl's speed is
miles per hour
After 2 hours, Carl will travel
miles.
2. The given line has equation

We write this in slope-intercept form by solving for y.

This is in the form
, where
is the slope.
When x=3,


When x=3, y=22
3. The given straight line graph that models the situation passes through:
(0,0) and (20,30).
The slope of this line is
Therefore the rate is $ 15 per ticket.
If the theater sells 150 tickets, the earnings will be:
dollars.