A thief steals a car at 1:00 PM and drives it at 40 km/h. The owner discovers the theft at 2:00 PM and sets off in another car at 50 km/h. When will the owner catch the thief?

1. A

   4:00 PM

2. B

   5:00 PM

3. C

   6:00 PM

4. D

   . 7:00 PM

Appeared in: DSSSB 6 September 2024

Explanation

• The thief gets a 1-hour head start, covering a distance of 40 km (40 km/h × 1 h).
• The owner gains on the thief at a relative speed of 10 km/h (50 km/h - 40 km/h).
• To cover the 40 km gap at a relative speed of 10 km/h, it will take 4 hours (40 km / 10 km/h).
• The owner starts at 2:00 PM, so adding the 4 hours taken to catch up gives a final time of 6:00 PM.

Why Other Options Were Wrong

• Option A: This time is too early. If the owner catches the thief at 4:00 PM, they would have driven for 2 hours, covering 100 km. In the same period, the thief would have driven for 3 hours, covering 120 km. The owner would still be behind.
• Option B: This time is also too early. If the owner catches the thief at 5:00 PM, they would have driven for 3 hours, covering 150 km. The thief would have driven for 4 hours, covering 160 km. The owner would still be 10 km behind.
• Option D: This time is too late. The calculation shows the catch-up happens after 4 hours from the owner's start time (2:00 PM), which is 6:00 PM, not 7:00 PM. At 7:00 PM, the owner would have traveled 250 km, while the thief would have traveled 240 km; the owner would have already passed the thief an hour earlier.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain This question tests the application of concepts of Time, Speed, and Distance, specifically focusing on relative speed in a chase scenario as background academic context rather than a clinical decision trigger.
• This is a general aptitude question testing mathematical reasoning.
• While not directly clinical, the logical and calculation skills are essential for tasks like drug dosage calculations, IV drip rate monitoring, and interpreting time-sensitive data in a clinical setting.
• What if? - If the stem changed one defining clue so that 6:00 PM no longer matched, reassess the option whose mechanism, classification, or indication now fits the revised presentation.

How to Approach the Question

• First, identify the key information: speeds of both individuals and their start times.
• Calculate the head start distance gained by the person who started earlier. In this case, the thief travels for one hour alone.
• Determine the relative speed. Since they are moving in the same direction, subtract the slower speed from the faster speed.
• Use the formula Time = Distance / Speed. Here, the 'Distance' is the head start distance, and 'Speed' is the relative speed.
• The result is the time it takes for the chaser to catch up. Add this time to the chaser's start time to find the final answer.

Concept Tested & Keywords

• Concept Tested: This question tests the application of concepts of Time, Speed, and Distance, specifically focusing on relative speed in a chase scenario.
• Stem keywords: thief, car, 1:00 PM, 40 km/h, owner, 2:00 PM, 50 km/h
• Lead-in keywords: When will

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QFcSi_tO-oG45hXf_Noec6

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