A train of length L is traveling at a constant velocity and passes a pole in t seconds. If the same train travelling at the same velocity passes a platform in 6t seconds, then what is the length of the platform? Choices.
A) l
B) 3 l
C) 5 l
D) 7 l
E) 9 l

Rationale: "the train passes a pole in t seconds , so velocity v = l / t ( l + p ) / v = 6 t ( l + p ) / ( l / t ) = 6 t p = 5 l the answer is c ."
Answer: C