Logic riddles can be classified according to the type of logic they use and the difficulty of the riddle. People have to use deductive reasoning to solve some riddles, and inductive reasoning to solve others. Inductive reasoning includes probability, which is a common topic for logic riddles. Deductive reasoning involves the use of general rules to infer specific pieces of information. Simple logic riddles are more suitable for kids and difficult ones are suitable for more advanced logicians.
Deductive reasoning is the most common type of logic required for logic riddles. Riddles relating to deductive reasoning present the reader with some general rules and ask them to infer a specific piece of information based on those rules. An example involves three opaque containers of coins, which are all labeled incorrectly: one jar contains 1975 pennies, one contains 2005 pennies and the other contains a mixture of 1975 and 2005 pennies. The person solving the puzzle is allowed to take one coin from one container and then must label all three correctly. The rule that no containers are labeled correctly can be used along with deductive reasoning to determine the contents of each jar after pulling one coin out of one container.
Another type of logic required for some logic riddles is inductive reasoning. Inductive reasoning focuses on probability, and while the logician can’t be entirely sure he or she is correct, he or she can choose the most probable solution. One inductive reasoning riddle focuses on a game show with three doors: two contain bags of coal and the other contains a bag of gold. The show’s player chooses one door, and then the host opens one of the other doors to reveal a bag of coal. The player is offered the chance to change doors, and using inductive reasoning can infer whether it is better to change his or her choice or stick with the original door.
Types of logic riddles can also be classified according to their difficulty. Difficult riddles require long chains of inductive or deductive reasoning in order to arrive at the correct solution. One example of a difficult riddle is one in which a king places three hats on the heads of three wise men and tells them that at least one of the hats is blue. They are able to deduce the colors of their hats by looking at the colors of the hats worn by the other wise men. To solve the riddle, the player has to work out how this was done.
Simple logic riddles are another type of logic riddles more suitable for children. One example is a riddle in which a sign-maker assigns values to individual letters based on a logical rule. The children are presented with four total prices for four different names and have to determine the rule based on them. This can be completed by looking at the common letters across the different names and determining their numerical value.