A 400 meter long train crosses a platform in 45 seconds while it crosses a signal pole in 30 seconds. What is the length of the platform?	Choose the correct choice from the following answers.
A) 200	B) 400	C) 350	D) 1800	E) 45
Speed = [400 / 30] m/sec = 40/3 m/sec.   Let the length of the platform be x meters.   Then, x + 400 / 45= 40/3   3(x + 400) = 1800 è x = 200 m. 200nswer: 200
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A 400 meter long train crosses a platform in 45 seconds while it crosses a signal pole in 30 seconds. What is the length of the platform?