In what time will a railway train 80 m long moving at the rate of 40 kmph pass a telegraph post on its way?  Choose the correct choice from the following choices.
A) 3
B) 5
C) 4
D) 6.4
E) 7.2

Rationale: "t = 80 / 40 * 18 / 5 = 7.2 sec answer : e"
Answer: E