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A train 200 m long crosses a 100 m platform at 36 km per hour. It takes:
A20 seconds
B25 seconds
C30 seconds
D36 seconds
Answer & Solution
Correct answer: C. 30 seconds
1. To cross a platform the train must cover its own length plus the platform's length.
2. That total is 200 + 100 = 300 m.
3. Convert the speed: 36 x 5 / 18 = 10 metres per second.
4. The time is 300 / 10 = 30 seconds.
5. Using only the train's length would give 20 seconds, which is the trap distractor here.
_Source: NCERT Class 8 Maths, Ch 11 'Direct and Inverse Proportions', S11.3 Inverse Proportion_
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