Correct Answer: Option B
2 kmph = (2 x (5/18) m/sec.
= (5/9) m/sec.
4 kmph = (4 x (5/18)) m/sec = 10/9 m/sec.
Let the length of the train be x metres and its speed by y m/sec.
Then, (x)/(y-(5/9)) = 9 and (x)/(y-(10/9)) = 10.
Therefore, 9y - 5 = x and 10(9y - 10) = 9x
=> 9y - x = 5 and 90y - 9x = 100.
On solving, we get: x = 50.
Therefore, Length of the train is 50 m.
Download our app for free and access thousands of MCQ questions with detailed solutions