Lateral thoughtIf it takes two men two hours to dig a hole five foot deep, how deep will a hole by dug by ten men in two hours?
The answer should be twenty-five foot deep. However this fails to take into account the fact that ten men cannot dig as well as two men in the same space. Not only would they be more inclined to do less work, the spades would get in the way of the other men.
This is the principle of lateral thought-it goes against logic because things in the real world aren't all that logical. You need to take into account all the factors and also the meaning of the words (another example would be "How long would it take to dig half a hole?"-you can't dig half a hole.)
Lateral problems seem to be isolated from maths. In fact maths is full of lateral problems. For example What is 100 shared between no people? The answer is any number whatsoever.
Other lateral problems are:
If one egg takes three minutes to boil, how long do two eggs cook? Answer: three minutes (more energy is needed to boil the water than the eggs).
If a knot in a 5 ft rope takes five minutes to undo, how long would a knot in a 10 ft rope take to undo? Answer: Also five minutes (the length of rope has nothing to do with the complexity of the knot).