Unstable traffic flow occurs when drivers accelerate and brake too often. Unstable traffic flow wastes energy. The table below gives one example of traffic speeds, in
lometers per hour
), man
o
Time (p.m.)
Speed (km/h)
4.00
30
4.10
20
4:20
50
4:30
70
4:40
20
4:50
7 0
5:00
20
What is the mean speed, in km/h, in this situation?
You may use the calculator
A 20
B 30
C 40
D 50