A train speeds past a pole in 15 seconds and a platfrom 100 m long in 25 seconds. Its length is :
Select the correct option:
A) 100 m	B) 125 m	C) 130 m	D) 150 m	E) None
Sol.   Let the length of the train be x metres and its speed be y m/sec.   They, x / y = 15 ⇒ y = x/15   ∴ x + 100 / 25 = x / 15 ⇔ x = 150 m.   Answer 150 m
<result>D</result>
A train speeds past a pole in 15 seconds and a platfrom 100 m long in 25 seconds. Its length is :