A 300 metre long train crosses a platform in 39 seconds while it crosses a post in 18 seconds. What is the length of the platform?  Choose the correct answer
A) 150 m
B) 350 m
C) 420 m
D) 600 m
E) 700 m
Explanation:   Length of the train = distance covered in crossing the post = speed × time = speed × 18   Speed of the train = 300/18 m/s = 50/3 m/s   Time taken to cross the platform = 39 s   (300+x)/(50/3) = 39 s where x is the length of the platform   300+x = (39 × 50) / 3 = 650 meter   x = 650-300= 
<gadget id="calculator">650-300</gadget>
<output>350</output>
350 meter   Answer: Option 350 m
<result>B</result>
A 300 metre long train crosses a platform in 39 seconds while it crosses a post in 18 seconds. What is the length of the platform?