A 750 m long train crosses a platform in 39 sec while it crosses a signal pole in 18 sec. What is the length of the platform?
Choose one:
A) 300
B) 875
C) 360
D) 770
E) 380

Rationale: "speed = 750 / 18 = 125 / 3 m / sec . let the length of the platform be x meters . then , ( x + 750 ) / 39 = 125 / 3 = > x = 1625 m . l = 1625 - 750 = 875 answer : option b"
Answer: B