At a Science Olympiad relay, three teammates move a sensor cart:

• Student A: 120 m in 20 s

• Student B: 80 m in 15 s

• Student C: 100 m in 25 s

What is the overall average speed of the cart?

A school bus travels 3.0 km in 5 min, waits in traffic for 2 min (no movement), then goes 2.5 km in 4 min. What is the average speed for the entire trip (in km/min)?

A swimmer’s workout is recorded in a table of segment distances:

• 0–2 min: 150 m

• 2–6 min: 300 m

• 6–7 min: 50 m

What is the average speed for the whole 7 minutes (in m/min)?