Originally posted by: DrPizza
seems to me that those "brain teasers" will actually give the company some indication of intelligence and problem solving ability. Anyone can get an A in college classes. I've known way too many people who are "book smart" but can't apply that knowledge.
QFT.
The problem with standardized qualifications, is that they may not discriminate adequately. It may be possible to rote learn your way into a qualification, but that doesn't make you good at your job.
There's more to working than just having the core knowledge of the subject at hand. The employer is looking for ability to think and tackle problems that haven't been considered before; an ability to spot obvious errors in logic; creativity and imagination and social capability. Most higher end jobs need some degree of imagination and social interaction.
Also remember than every company wants the best employees, it wants to select the best, leaving the dregs for its competitors, so it needs to have a selection method that will do what needs to be done.
So this is why you get questions like the man-hole one. It matters less that you get the answer right, but that you can show some sort of logical thought process:
E.g. Circles have a number of interesting properties. The circle is the shape with the highest area/perimeter ratio. This makes round manhole covers stronger than other shapes.
or
The circle has the best surface area/diameter ratio. This means that the circle is the smallest shape that would allow a piece of equipment with a certain diameter to pass.
These may not be the main reason, they may not even be right - but they show a clear method of reasoning, from a basic starting point - and that is more important that just coming out with an answer that you remember from browsing a forum.
There are lots of similar questions - I recently saw one '"You are suddenly shrunk to 1:50 scale, keeping your proportions preserved, and placed in a blender which starts in 60 seconds. What do you do?"
The answer is simple: you jump. But I would want to hear some sort of reasoning - be it mathematical:
The energy expended by a muscle is proportional to its volume (which in this case is reduced by 1:50^3), the mass is also reduced proportionally to 1:50^3. Since the height you can jump h = E /mg - if you reduce E and M proportionally, the shrinking doesn't change the height you can jump (so unless the blender is 3 feet high, you'd have no problem jumping out).
or be it observationally:
I can jump about 50% my height. A bigger creature like an elephent can jump maybe 5%. A cat can jump 500% its height, and a flea 5000% its height. This suggests the height a creature can jump decreases much more slowly than its size - so a 50x reduction in size, may only reduce jump height by a factor of 5x - which would give a good chance of clearing the blender.