A, B and C are in a cycle race of 18000 m. A cycles at twice the speed of B. C cycles at the same speed as B. C finishes the race in 50 minutes. How far was B from the finishing line when A finished the race?

1. A

   9000 m

2. B

   8997 m

3. C

   9001 m

4. D

   8995 m

Appeared in: DSSSB 12 August 2024

Explanation

• First, calculate the speed of cyclist C, which is 18000 m / 50 min = 360 m/min. Since B cycles at the same speed, B's speed is also 360 m/min.
• Cyclist A's speed is twice B's speed, so A's speed is 2 * 360 m/min = 720 m/min.
• Next, find the time it takes for A to finish the 18000 m race: Time = Distance / Speed = 18000 m / 720 m/min = 25 minutes.
• In these 25 minutes, calculate the distance B has traveled: Distance = Speed * Time = 360 m/min * 25 min = 9000 m.
• Finally, the distance B is from the finishing line is the total distance minus the distance covered: 18000 m - 9000 m = 9000 m.

Why Other Options Were Wrong

• Option B: This value is an arbitrary number close to the correct answer but does not result from the correct calculation.
• Option C: This is another arbitrary value. The calculation is precise and does not result in a number slightly over 9000.
• Option D: This value is also incorrect and does not follow the principles of speed, distance, and time. The relationship between the speeds (2:1) means that when the faster person finishes, the slower person is exactly halfway.

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Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculations involving Speed, Distance, and Time as background academic context rather than a clinical decision trigger.
• This type of calculation is fundamental in nursing for determining medication infusion rates. For example, if a drug needs to be administered over a specific time, nurses calculate the flow rate in mL/hour or drops/minute.
• It is also used for calculating fluid balances, where the rate of intake and output over time must be accurately tracked.
• What if? If A's speed was three times B's speed, A would finish in 50/3 minutes (approx 16.67 min). In that time, B would have covered 360 m/min * (50/3) min = 6000 m. B would then be 18000 - 6000 = 12000 m from the finish line.

How to Approach the Question

• First, identify all the given variables: total distance (18000 m), relationship between speeds (A=2B, B=C), and time for C (50 min).
• Use the formula Speed = Distance / Time to calculate the speed of C. This will also give you the speed of B.
• Calculate the speed of A based on its relationship with B's speed.
• Determine the time it takes for A to complete the race using the formula Time = Distance / Speed.
• Use this time to find out how far B has traveled in the same duration.
• Subtract the distance B has traveled from the total race distance to find the remaining distance from the finish line.

Concept Tested & Keywords

• Concept Tested: Calculations involving Speed, Distance, and Time
• Stem keywords: cycle race, 18000 m, twice the speed, 50 minutes
• Lead-in keywords: How far

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QJ52s2FPhzU82iKaSk5SPF

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