Correct Answer: 79.2 km/hr
Explanation:
Step 1: Understand the given data
Step 2: Let the length of the train be L meters
Step 3: When it passes the bridge
Step 4: Solve the equation
L + 264 = (L / 8) × 20 L + 264 = (20L) / 8 L + 264 = (5L) / 2 Multiply both sides by 2: 2L + 528 = 5L 528 = 5L - 2L 528 = 3L L = 176 meters
Step 5: Find the speed of the train
Speed = L / 8 = 176 / 8 = 22 m/s Convert to km/hr: 22 × 18 / 5 = 79.2 km/hr
Answer: The speed of the train is 79.2 km/hr
This is a classic speed–distance–time problem where the trick is to understand that when a train crosses a point (like a pole), it covers its own length, and when it crosses a bridge, it covers its own length plus the bridge length. Problems like this test your algebraic setup and unit conversion skills.
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