A certain distance is covered in 2 hours 45 minutes at 4 km/h. How much time (in minutes and seconds) will be needed to cover the same distance at 16.5 km/h?

Difficulty: Easy

Correct Answer: 40 min

Explanation:


Introduction / Context:
The distance remains identical; thus time scales inversely with speed. First compute the distance using the initial speed and time, then divide by the new speed to find the new time.


Given Data / Assumptions:

  • Speed1 = 4 km/h; Time1 = 2 h 45 min = 2.75 h.
  • Speed2 = 16.5 km/h.


Concept / Approach:
Distance D = v1 * t1. New time t2 = D / v2.


Step-by-Step Solution:

D = 4 * 2.75 = 11 kmt2 = 11 / 16.5 h = 2/3 hConvert 2/3 h = 40 minutes


Verification / Alternative check:
Proportion: t2 / t1 = v1 / v2 = 4 / 16.5 ≈ 0.2424; 0.2424 * 165 minutes ≈ 40 minutes.


Why Other Options Are Wrong:
41 min 15 sec is a near-miss; 45 or 90 minutes contradict the inverse-speed relationship.


Common Pitfalls:
Not converting hours/minutes consistently; rounding before the final step.


Final Answer:
40 min

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