Many of the answers should give you a strategy for thinking, which will carry over to many other problems and provide you with thinking and problem-solving methods. There is no time limit for these questions (with exceptions as noted). Be aware that there may be more than one way to arrive at an answer to a question. Just remember, a person who can solve problems efficiently either knows a particular strategy for the type of problem or extract something from the problem that is curious to him or her and that leads to the next step toward a solution.
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