A 420 meter long train crosses a platform in 60 seconds while it crosses a signal pole in 30 seconds. What is the length of the platform?	Pick: A) 120 B) 840 C) 350 D) 420 E) 210
Speed = [420 / 30] m/sec =14 m/sec.   Let the length of the platform be x meters.   Then, x + 420/ 60 = 14   x + 420 = 840 è x = 420m. Answer: 420
<result>D</result>
A 420 meter long train crosses a platform in 60 seconds while it crosses a signal pole in 30 seconds. What is the length of the platform?