A car covers 300 km in 15 hours. What is the speed of the car (in km/h)?

Introduction / Context:
The fundamental speed relation is speed = distance / time. This direct application checks comfort with basic units and arithmetic.

Given Data / Assumptions:

• Distance = 300 km.
• Time = 15 h.
• Uniform speed throughout.

Concept / Approach:
Apply speed = distance / time and simplify.

Step-by-Step Solution:
Speed = 300 / 15 = 20 km/h.

Verification / Alternative check:
At 20 km/h for 15 h, distance = 20*15 = 300 km, which matches the given distance.

Why Other Options Are Wrong:
25, 24, and 15 km/h do not satisfy 300 = speed * 15 given exact integers.

Common Pitfalls:
Accidentally converting units (e.g., to minutes) without need; overcomplicating a straightforward division.

Final Answer:
20 km/h