In what time will a train 90 m long cross an electric pole, it its speed be 72 km/hr?  Pick:
A) 1.5
B) 2.5
C) 3.5
D) 4.5
E) 5.5

Rationale: "speed = 72 * 5 / 18 = 20 m / sec time taken = 90 / 20 = 4.5 sec . answer : d"
Answer: D