A red ball moves horizontally in a 30 m long tube. The position of the ball in meters over time is shown below.
Position
(meters)
15+
12+
9+
6+
3+
Time
(seconds)
8
12
16 20 24
-3t
-6+
-9+
-12+
-15+
What is the displacement of the red ball between 12 s and 24 s?