Difficulty: Easy
Correct Answer: 45
Explanation:
Introduction / Context:This is a distance-speed-time conversion problem. You first compute the distance using walking speed and time, then compute cycling time using the cycling speed. Finally, convert hours to minutes.
Given Data / Assumptions:
Concept / Approach:Distance = speed * time. Convert mixed time (hours and minutes) into hours for calculation. Then time = distance / speed for the cycling part. Convert final time into minutes.
Step-by-Step Solution:
Convert 3 hours 36 minutes to hours: 36 minutes = 36/60 = 0.6 hours. So walking time = 3 + 0.6 = 3.6 hours. Compute distance: distance = 5 * 3.6 = 18 km. Cycling time in hours = distance / speed = 18/24 hours. Simplify 18/24 = 3/4 = 0.75 hours. Convert 0.75 hours to minutes: 0.75 * 60 = 45 minutes.Verification / Alternative check:If he cycles for 45 minutes, that is 45/60 = 0.75 hours. At 24 km/h, distance = 24 * 0.75 = 18 km, matching the walking distance.
Why Other Options Are Wrong:
40 minutes would correspond to 24*(40/60) = 16 km, short of 18 km. 50 and 55 minutes would exceed 18 km at 24 km/h. 60 minutes would give 24 km, much larger than the distance calculated.Common Pitfalls:Forgetting to convert minutes to hours (or vice versa), or using 3.36 hours instead of 3.6 hours. Also, avoid mixing km/h with minutes directly without conversion.
Final Answer:45 minutes
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