A bus covers 400 km at 20 km/h. How much time does it take to cover this distance?
Aptitude
Time and Distance
Difficulty: Easy
Choose an option
-
A25 h
-
B5 h
-
C21 h
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D20 h
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ENone of these
Answer
Correct Answer: 20 h
Explanation
Introduction / Context:Time is distance divided by speed for uniform motion. The numbers lead to an exact integer solution.
Given Data / Assumptions:
- Distance = 400 km.
- Speed = 20 km/h.
Concept / Approach:Use time = distance / speed.
Step-by-Step Solution:Time = 400 / 20 = 20 h.
Verification / Alternative check:Check: 20 km/h for 20 h yields 400 km.
Why Other Options Are Wrong:25 h would imply 16 km/h; 5 h implies 80 km/h; 21 h implies ~19.05 km/h, none matching 20 km/h.
Common Pitfalls:Inverting the ratio and mistakenly multiplying speed by time instead of dividing distance by speed when solving for time.
Final Answer:20 h