Comment by sytelus

I think few people probably knows how textbooks are written. Given millions of students spend millions of hours on these textbooks, one would expect there is a great care taken in writing textbooks. This is often not true and it was very well described by Richard Feynman. He was so repulsed by the quality of textbooks that this Nobel prize winning physicist decided to be part of committee. To his surprise, in committee meetings no one came prepared, they often missed meetings and decisions were finally made ad-hoc. He was so frustrated by whole process that (I think) eventually gave up. I suspect similar thing happens in how exams are written. People who write questions aren't often deep thinkers who took at most care but rather low level leaf nodes who happen to have time for doing more work for peanuts.