Question:medium

If a train runs at 50 km/hr, it reaches 60 minutes earlier than its schedule time at its destination but if it runs at 8.33 m/s it reaches at its destination 300 minutes late, find the correct time for the train to complete its journey.

Show Hint

In speed-distance-time problems with two scenarios, always set up equations where the constant quantity (usually distance) is isolated. This allows you to equate the variable expressions and solve for the unknown.
Updated On: Mar 1, 2026
  • 10 hours
  • 6.5 hours
  • 7.44 hours
  • 13.3 hours
Show Solution

The Correct Option is A

Solution and Explanation

Step 1: Understanding the Concept:
This problem relates speed, distance, and time. Since the distance remains constant, we can use the formula \( \text{Distance} = \text{Speed} \times \text{Time} \).
Step 2: Key Formula or Approach:
1. Convert all units to km/hr and hours for consistency.
2. \( \text{Distance} (D) = S_1 \times (T - t_1) = S_2 \times (T + t_2) \), where \( T \) is the scheduled time.
Step 3: Detailed Explanation:
Speed 1 \( (S_1) = 50 \) km/hr.
Time difference 1: Reaches 60 minutes earlier \( = 1 \) hour early.
Speed 2 \( (S_2) = 8.33 \) m/s.
Convert \( S_2 \) to km/hr:
\[ 8.33 \text{ m/s} \approx \frac{25}{3} \times \frac{18}{5} = 5 \times 6 = 30 \text{ km/hr} \] Time difference 2: Reaches 300 minutes late \( = \frac{300}{60} = 5 \) hours late.
Let the correct (scheduled) time be \( T \).
Since distance \( D \) is the same:
\[ 50 \times (T - 1) = 30 \times (T + 5) \] \[ 5(T - 1) = 3(T + 5) \] \[ 5T - 5 = 3T + 15 \] \[ 2T = 20 \] \[ T = 10 \text{ hours} \]
Step 4: Final Answer:
The correct time for the train to complete its journey is 10 hours.
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