listing vs counting vs probability rules
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probability
summary
the essence of tackling gre probability questions lies in discerning which problem-solving technique to employ, be it listing, counting, or formal algebraic probability rules.
- identify the use of formal algebraic rules by the presence of algebraic expressions or the use of specific terms like 'mutually exclusive' or 'independent'.
- listing is most effective for problems with very short lists of fewer than ten possibilities, but it's rarely a complete solution technique on its own.
- counting techniques are suited for problems involving selections from a set with restrictions, indicating a focus on the selection process rather than algebraic computation.
- considering the complement of the desired outcome can simplify the calculation process, showcasing the need for creativity in problem-solving.
- developing the right approach to probability problems is a pattern-matching process that improves with practice and careful study of solution sets.
chapters
00:00
choosing the right tool
01:03
when to use algebraic rules
02:31
the role of listing in problem solving
03:57
counting techniques for selection problems
05:18
the importance of practice and pattern recognition