A goods train runs at the speed of 72 kmph and crosses a 240 m long platform in 26 seconds. What is the length of the goods train? Pick.
A) 230 m  B) 270 m  C) 643 m  D) 280 m  E) 270 m

Rationale: "speed = ( 72 x 5 / 18 ) m / sec = 20 m / sec . time = 26 sec . let the length of the train be x metres . then , x + 240 / 26 = 20 x + 240 = 520 x = 280 . answer : d"
Answer: D