Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases

Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases

How do I increase or decrease by a percentage?

  • Identify “before” & “after” quantities
  • Find percentage of “before” that we want:
    • Increase – add percentage to 100
    • Decrease – subtract percentage from 100

     

  • Write down a statement connecting “before” and “after”:
    • “after is a percentage of before”

     

  • Write down the statement as an equation using decimal equivalent
    • remember “is” means “=”

     

  • Substitute and solve

How do I find percentage profit (or loss)?

  • Calculate percentage profit (or loss)

  • You can identify whether there is a profit or loss
    • cost price < selling price = profit (positive)
    • cost price > selling price = loss (negative)

Worked Example

转载自savemyexam

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