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weighted averages ii (advanced)


mike mcgarry
lesson by mike mcgarry
magoosh expert

summary
the content delves into an advanced technique for solving weighted average problems, specifically designed for individuals with strong mathematical skills and visual thinking capabilities. it builds upon basic methods discussed in a previous lesson, introducing a proportional reasoning approach for problems involving only two groups.
  • introduces an advanced technique for solving weighted average problems, emphasizing its suitability for those with strong math skills.
  • recaps two basic methods from a prior lesson: summing subsections and multiplying subsection averages by proportions.
  • explains proportional reasoning for two-group weighted averages, where the total average lies closer to the average of the larger group, with distances on a number line reflecting the proportions of the group sizes.
  • demonstrates the advanced technique through examples, including calculating the average mass of vehicles on a ferry and determining the average salary difference between two classes of employees at a corporation.
  • highlights that understanding the reciprocal relationship between the distances from group averages to the total average and the proportions of the group sizes can be a time-saving strategy for tackling complex weighted average problems.
chapters
00:00
introduction to advanced techniques
01:30
proportional reasoning for two groups
03:03
applying advanced techniques: vehicle example
05:29
applying advanced techniques: corporate salary example