A man crosses a straight 600 m street in 5 minutes at constant pace. What is his speed in km/h?

Difficulty: Easy

Correct Answer: 7.2 km/h

Explanation:

Introduction / Context:Convert a meters-per-minute rate to km/h by appropriate unit conversions (m → km, min → h).

Given Data / Assumptions:

  • Distance = 600 m.
  • Time = 5 minutes.

Concept / Approach:First compute m/s or m/min, then convert to km/h. 1 m/s equals 3.6 km/h.

Step-by-Step Solution:

Speed = 600 m / 5 min = 120 m/minConvert to m/s: 120 / 60 = 2 m/sConvert to km/h: 2 * 3.6 = 7.2 km/h

Verification / Alternative check:Direct conversion: 0.6 km in 1/12 h → 0.6 * 12 = 7.2 km/h.

Why Other Options Are Wrong:They reflect wrong conversion factors between m/s and km/h, or minutes-to-hours errors.

Common Pitfalls:Using 3.0 instead of 3.6 for the m/s to km/h factor; forgetting to divide by 60 to get m/s.

Final Answer:7.2 km/h

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