How to answer Train Window Viva question

Students went to an Engineering Viva Exam.

The first guy goes into the class, and the professor begins the Viva with a question…

“Let’s say you are traveling by train and its getting hot. What will you do?”

“Open the window”… he answers.

“Very good”…the professor continues..

“Now…The window has a surface of 1.5 m2″… and

“The compartment has a volume of 12 m3″… and

“The train speeds 80 kph to the west”…

“The south wind is blowing at 5 mps”…

“How quickly will the space be refreshed?”

The student does not know the answer and fails the exam.

He gets out and tells the other students the question.

The second student goes in, and the professor begins with the question…

“Lets say you are traveling by train and it’s getting hot. What will you do?”

“Sir, I’ll take off my coat”… answers the student.

“But It’s very hot!”…Continues the professor.

“Then I’ll Take off my shirt and my baniyan also.”…. Student

“But It’s damn hot!”…The professor adamantly insists.

“Then I’ll take off my pants and socks, Sir.” ….. Student

“But You can’t sit naked in the train!!!! They will report you to the police”… said the angry professor.

The student confidently answers…

“Sir, whatever happens, I am not going to open that window!” ??