The Engineer's Interview

An engineering firm is looking to fill a position, and has interviewed a few dozen applicants. They've winnowed it down to just three candidates, and they're all bright, motivated, and experienced.

To make the final decision, the interviewer decides to pose one last question to each of them.

He tells the three interviewees, "So this building we're in, any idea how tall it is, down to the inch?" All three shake their heads.

Turning to the first he says, so if I gave you an accurate barometer, how would you determine the height?
The engineer pauses and says, "Well, I'd measure the pressure difference between the roof and ground, use that to find the change in altitude".

Nodding, the interviewer turns to the second candidate. "And you? How would you measure this?",

"Well" says the second engineer, "I would measure the shadow cast by the barometer and the shadow cast by the building. We know the length of one, we can find the length of the other".

"Very good!" said the interviewer, finally turning to the last engineer. "And you?"

After a moment's thought the third engineer finally says, "I think I'd just find the building manager, offer to give him a shiny new barometer if he told me how tall the building is."