At one of my interviews today, I was given a few of those notorious brain teasers. One of them, though, had a solution that is complete BS, so I'll blog about it with hopes that it'll be revised in the future...

So the problem as it was given to me goes like this:

You're at the pier where there's a destroyer, and a plane, say... an F-16, that was just offloaded. How would you find out how much this plane weighs?

One major problem with this particular version is that 1) destroyers don't carry planes, 2) F-16s are purely land-based fighters. But, I assume what they meant was that there was a carrier at the pier, and a plane (say, and F-14, which is a carrier-based fighter) was offloaded, and you're supposed to figure out how much it weighs.

The "solution" apparently is to put it back on the ship, mark the displacement, take it off, then put weights on the carrier until you reach the same displacement. The problem is, an F-14 weighs about 20 tons while an aircraft carrier has a displacement of 60,000 to 100,000 tons. There's no way you can mark the displacement accurately enough (mind you, waters are never that calm) to be able to measure changes to get even semi-reasonable results (or at least results that are more accurate than guessing). And if you're going to ask engineers such questions, you might as well make sure your solutions are realistic because that's what engineers do.

So, just in case anyone's listening, the problem should either be re-worded so the solution is feasible, or a solution that's feasible should be presented for this given problem (or just don't ask silly questions like these in the first place).